
<PAGE>
 
                                 EXHIBIT 99.11



          DATED                23rd December         1993
          -----------------------------------------------



                         (1) IBM UNITED KINGDOM LIMITED

                                    - and -

                        (2) ACC LONG DISTANCE UK LIMITED

                                    - and

                                  (3) ACC CORP



                                   __________

                              U N D E R L E A S E

                                       of

                       Tenth Floor at The Chiswick Centre
                       414 Chiswick High Road  London W4
                                   __________



                              ASHURST MORRIS CRISP
                                Broadwalk House
                                5 Appold Street
                                London EC2A 2HA

                               Tel: 071-638-1111

                               Fax: 071-972-7990


                                                                 REF:  VTH/ID167
                                                                 DATE:  17/11/93
<PAGE>
 
                                    CONTENTS
                                    --------

Clause         Heading
------         -------
or Schedule
-----------
               PARTICULARS

        1.     DEFINITIONS

        2.     INTERPRETATION

        3.     DEMISE

        4.     THE TENANT'S COVENANTS
        4.1.   Rents
        4.2.   Outgoings and VAT
        4.3.   Repair, cleaning and decorating
        4.4.   User and Restrictions on Use
        4.5.   Waste and Alterations
        4.6.   Aerials Signs and Advertisements
        4.7.   Obstruction
        4.8.   Statutory Obligations and Fire Precautions
        4.9.   Access to Landlord and Notice of Repair
        4.10.  Dealings
        4.11.  Landlord's Costs
        4.12.  The Planning Acts
        4.13.  Plans, Documents and Information
        4.14.  Indemnities
        4.15.  Disposal Boards and Viewing
        4.16.  Encroachments
        4.17.  Yield Up
        4.18.  Interest on Arrears
        4.19.  Statutory Notices
        4.20.  Defective Premises
        4.21.  Compliance with Regulations
        4.22.  Outside Business Hours
        4.23.  Superior Lease Covenants
        4.24.  Option to Determine

        5.     THE LANDLORD'S COVENANTS

        6.     INSURANCE
        6.1.   Tenant's Insurance Covenants
        6.2.   Suspension of Principal Rent

        7.     PROVISOS
        7.1.   Re-Entry
        7.2.   Rights and Easements
        7.3.   Disputes with Adjoining Occupiers
        7.4.   Exclusion of Use Warranty
        7.5.   Representations
        7.6.   Tenant's Property
        7.7.   Compensation on Vacating
        7.8.   Covenants relating to Adjoining Premises
        7.9.   Service of Notices

                                      -i-
<PAGE>
 
        7.10.  Value Added Tax
        7.11.  Exclusion of Landlord and Tenant Act 1954
        7.12.  Jurisdiction

THE FIRST SCHEDULE -  Part 1 - Rights and Easements Granted
                      Part 2 - Rights and Easements Excepted and Reserved

THE SECOND SCHEDULE - Principal Rent and Rent Review

THE THIRD SCHEDULE - Covenants by the Surety

THE FOURTH SCHEDULE - The Regulations

                                      -ii-
<PAGE>
 
                                  PARTICULARS
                                  -----------


DATE                     :    23rd December                    1993

--------------------------------------------------------------------------------

LEASE OR UNDERLEASE      :    UNDERLEASE

--------------------------------------------------------------------------------

LANDLORD                 :    IBM UNITED KINGDOM LIMITED whose registered office
                              is at P.O. Box 41 North Harbour Portsmouth
                              Hampshire PO6 3AU
                              
TENANT                   :    ACC LONG DISTANCE UK LIMITED (Company Registration
                              Number 2671855) whose registered office is at 2-3
                              Cursitor Street London EC4A 1NE
                              
SURETY                   :    ACC CORP whose registered office is at 39 State
                              Street City Rochester NY 14614 United States of
                              America

--------------------------------------------------------------------------------

PREMISES                 :    the tenth floor of the Building shown for the
                              purpose of identification only edged red on the
                              Floor Plan and being more particularly described
                              in Clause 1
                                
--------------------------------------------------------------------------------
                                
CONTRACTUAL TERM         :    10 years from and including the 29th day of
                              September 1993 until and including the 28th day of
                              September 2003
                                
--------------------------------------------------------------------------------

PRINCIPAL RENT           :    EIGHTY SIX THOUSAND FIVE HUNDRED AND EIGHTY POUNDS
                              ((Pounds)86,580) per annum
                                
--------------------------------------------------------------------------------

RENT COMMENCEMENT DATE   :    the 24th day of June 1995

--------------------------------------------------------------------------------

INITIAL PROVISIONAL
SERVICE CHARGE           :    TWENTY TWO THOUSAND TWO HUNDRED AND THIRTY POUNDS
                              ((Pounds)22,230) per annum

--------------------------------------------------------------------------------

PERMITTED USER           :    high class offices within Class II of the Schedule
                              to the Town and Country Planning (Use Classes)
                              Order 1972

--------------------------------------------------------------------------------

INTERIOR DECORATING YEARS  :  1998

--------------------------------------------------------------------------------
<PAGE>
 
       THIS UNDERLEASE made on the date and between the parties specified in the
Particulars

     WITNESSES as follows:-


1.   DEFINITIONS
     -----------

     In this Lease and the Schedules the following words and expressions have
the following meanings:-

          "Accountant" means any person or firm appointed by the Landlord
(including an employee of the Landlord or a Group Company of the Landlord) to
perform the functions of the Accountant under this Lease

          "Act of Insolvency" means:

          in relation to a corporate body that:-

               it is unable to pay its debts as defined in section 123 of the
               Insolvency Act 1986 (referred to as "the Act" in the remainder of
               this definition) (and for the purposes of interpreting that
               section the words "if it is proved to the satisfaction of the
               court that" in sub-sections 123(l)(e) and 123(2) shall be
               ignored) or

               a proposal is made for a voluntary arrangement under Part I of
               the Act or

               a petition is presented for an administration order under Part II
               of the Act or

               a receiver and (or) manager or administrative receiver is
               appointed whether under Part III of the Act or otherwise or

               it goes into liquidation as defined in Section 247(2) of the Act
               (other than a voluntary winding up solely for the purpose of
               amalgamation or reconstruction while solvent) or

               a provisional liquidator is appointed under Section 135 of the
               Act or

               a proposal is made for a scheme of arrangement under Section 425
               of the Companies Act 1985

          and in relation to an individual that:-
<PAGE>
 
                                     - 2 -


               an application is made for an interim order or a proposal is made
               for a voluntary arrangement under Part VIII of the Act or

               a bankruptcy petition is presented to the Court or his
               circumstances are such that a bankruptcy petition could be
               presented under Part IX of the Act or

               he enters into a deed of arrangement

          "Adjoining Property" means any neighbouring or adjoining land or
premises now or at any time during the Term belonging to the Landlord or a Group
Company of the Landlord

          "Building" means the land and building(s) known as The Chiswick Centre
Chiswick  London W4 shown for the purpose of identification only edged red on
the Site Plan

          "Business Day" means a day on which clearing banks in the City of
London are (or would be but for a strike lockout or other stoppage affecting
particular banks or banks generally) open during banking hours and "Business
Days" shall be interpreted accordingly

          "Business Hours" means 8.30 a.m. to 6.30 p.m. Mondays to Fridays
(except Bank Holidays) or such other hours as the Landlord may determine

          "Car Park" means the car parking areas shown for the purpose of
identification only edged green on the Site Plan

          "Common Parts" means all areas which are from time to time during the
Term provided by the Landlord for common use and enjoyment by the general public
and (or) by tenants and the occupiers of the Building and all persons expressly
or by implication authorised by them including without limitation the pedestrian
areas and walkways forecourts car parking areas landscaped areas entrance halls
landings hoists lifts lift-shafts staircases escalators and passages

          "Conduits" mean all conduits sewers drains mains ducts pipes gutters
watercourses wires cables fibres channels flues and all other conducting media
including any fixings louvres cowls and any other ancillary apparatus

          "Contractual Term" has the meaning given in the Particulars
<PAGE>
 
                                     - 3 -

          "Development" has the meaning given by Section 55 of the Town and
Country Planning Act 1990

          "Exclusion Agreement" means an agreement contained or referred to in
an underlease of the Premises or any part thereof authorised by Order of the
Court under Section 38(4)(a) of the 1954 Act excluding in relation to that
underlease the provisions of Sections 24 to 28 of the Landlord and Tenant Act

          "Floor Plan" means the plan annexed to this Lease and marked "Floor
Plan"

          "Group Company" means any company which is for the time being a
subsidiary or a holding company or another subsidiary of the holding company in
each case within the meaning of Section 736 of the Companies Act 1985 which
Section shall for this purpose be deemed not to have been amended by subsequent
legislation

          "Initial Provisional Service Charge" means the annual amount referred
to in the Particulars

          "Insurance Rent" means the sums to be reimbursed by the Tenant to the
Landlord comprising a reasonable proportion of the cost to the Landlord from
time to time of:-

     (a)  insuring the Building or reimbursing the Superior Landlord therefor in
          accordance with the Landlord's obligations contained in this Lease and
          the Superior Lease and

     (b)  effecting insurance against loss of the Principal Rent for a period of
          three years and

     (c)  insuring in such amount and on such terms as the Landlord or the
          Superior Landlord shall reasonably consider appropriate against all
          liability of the Landlord or the Superior Landlord to third parties
          arising out of or in connection with any matter relating to the
          Building

          "Insured Risks" means fire storm tempest flood earthquake lightning
explosion impact aircraft (other than hostile aircraft) and other aerial devices
and articles dropped therefrom riot civil commotion and malicious damage
bursting or overflowing of water tanks apparatus or conduits subsidence heave
and such other risks as the Landlord may in its reasonable discretion from time
to time determine

          "Interest" means interest (compounded at monthly rests) both before
and after any judgement at the Interest Rate then prevailing during the period
beginning on the date 14 days after the relevant payment is due and has been
demanded and ending on the date on which the relevant payment is received by way
of cleared funds
<PAGE>
 
                                     - 4 -

          "Interest Rate" means Four percentage points above the base lending
rate from time to time in force of National Westminster Bank PLC or such other
Bank whose Chairman is a member of the Committee of London Clearing Bankers as
the Landlord may from time to time nominate in writing or should such base
lending rate cease to exist such other rate of interest as the Landlord (acting
reasonably) shall deem to be most closely comparable with the said base lending
rate

          "Interior Decorating Years" has the meaning given in the Particulars

          "Landlord" means the party described as the Landlord in the
Particulars and includes the party for the time being entitled to the reversion
immediately expectant on the determination of the Term

          "Landlord and Tenant Act" means  the Landlord and Tenant Act 1954

          "this Lease" means this Lease and any document which is made
supplemental to this Lease or which is entered into pursuant to or in accordance
with the terms of this Lease

          "Lettable Areas" means all parts of the Building which from time to
time are either occupied or used by a tenant or tenants or capable or intended
of being so occupied or used

          "Outside Business Hours Charge" means the whole of the cost incurred
by the Landlord in carrying out or providing any of the Services (which are not
normally provided by the Landlord outside the Business Hours) at the request of
the Tenant outside Business Hours (including but not limited to costs and
expenses in the nature of those set out in Part C of the Fourth Schedule) or in
the event of any of the Services being carried out or provided outside Business
Hours to the Tenant (at the request of the Tenant) and to any other tenant or
tenants of the Building a fair proportion thereof as reasonably and properly
determined by the Landlord

          "Particulars" means the immediately preceding section of this Lease
headed "Particulars"

          "Permitted Underlease" means an underlease of the whole of the
Premises which:-

     (a)  is granted without any fine or premium

     (b)  reserves a rent not less than the greater of the then open market rent
          of the Premises and the Principal Rent then payable
<PAGE>
 
                                     - 5 -

     (c)  incorporates provisions for the review of rent at the same times and
          on the same basis as in this Lease  and

     (d)  is (so far as is consistent with an underlease) in a form similar to
          this Lease  and

     (e)  incorporates an Exclusion Agreement

          "Permitted User" has the meaning given in the Particulars

          "Planning Acts" means the Town and Country Planning Act 1990 the
Planning (Listed Buildings and Conservation Areas) Act 1990 the Planning
(Hazardous Substances) Act 1990 the Planning (Consequential Provisions) Act 1990
and the Planning and Compensation Act 1991

          "Plant" means all apparatus plant machinery and equipment within the
Building from time to time including without limitation lifts lift-shafts hoists
escalators stand-by generators and boilers and items relating to mechanical
ventilation heating cooling public address telephone and closed-circuit
television and building management systems the fire alarm system the sprinkler
system the security systems the smoke detection and heat detection equipment and
systems and the cleaning cradle equipment

          "Premises" means the part of the Building described as the Premises in
the Particulars and includes:-

     (a)  the plasterwork and decorative finishes applied to the internal
          surfaces of the external and load-bearing walls and columns of the
          Building but not any other part of the external or load-bearing walls
          and columns

     (b)  the floor finishes and floor trunking finishes

     (c)  the ceiling finishes any suspended ceiling and the void above any
          suspended ceiling so that the upper limit of the Premises includes
          such finishes suspended ceiling and void but does not extend to
          anything above them

     (d)  the entirety of the non-load-bearing internal walls and glass
          partitions wholly within the Premises
<PAGE>
 
                                     - 6 -

     (e)  the plasterwork and decorative finishes applied to the internal
          surfaces of the internal non-load-bearing walls and the internal
          surface of partitioning or balustrading dividing the Premises from
          other parts of the Building and the internal decorative surfaces of
          the window frames and window furniture in the windows which form part
          of the external envelope of the Building or which separate the
          Premises from any atria within the Building

     (f)  the internal surfaces and door furniture of the doors and the door
          frames

     (g)  all additions and improvements to the Premises

     (h)  all the Landlord's fixtures and fittings and fixtures of every kind
          which shall from time to time be in or upon the Premises (whether
          originally affixed or fastened to or upon the Premises or otherwise)
          except any such fixtures installed by the Tenant

     (i)  all Conduits in on under or over and exclusively serving the Premises
          except those belonging to a statutory undertaker or public utility

and references to the "Premises" in the  absence  of  any  provision to the
contrary include any and every part of the Premises

          "Principal Rent" has the meaning given to it in the Particulars and in
paragraph 1 of the Second Schedule

          "Rent Commencement Date" has the meaning given in the Particulars

          "Rents" means the Principal Rent the Insurance Rent and the other
payments reserved as rent and referred to in Clause 3

          "Replies to Preliminary Enquiries" means the replies given to the
enquiries raised by Hopkins and Wood, Solicitors for the Tenant on grant of a
Lease dated 16th August 1993 by Ashurst Morris Crisp, Solicitors for the
Landlord dated 12th October 1993 and their letter to Hopkins and Wood dated 5th
November 1993

          "Service Charge" means the aggregate of the sums which the Landlord is
required to pay to the Superior Landlord pursuant to Clauses 1(1)(iii) and
1(1)(iv) of the Superior Lease
<PAGE>
 
                                     - 7 -

          "Services" means the services facilities and amenities to be provided
by the Superior Landlord for the benefit of the Building

          "Site Plan" means the plan annexed to this Lease and marked "Site
Plan"

          "Superior Lease" means a lease dated 8th March 1984 and made between
(1) Clerical Medical and General Life Assurance Society and (2) the Landlord and
the lease supplemental thereto dated 19th April 1985 and made between the same
parties and includes where the context admits any lease whether mediate or
immediate out of which that lease was created

          "Superior Lease Covenants" means the covenants agreements and
provisions affecting the Premises contained in any Superior Lease and on the
part of the tenant to be performed and observed except the covenant for payment
of rent

          "Surety" means the party (if any) described as the Surety in the
Particulars and includes:-

     (a)  any party who enters into covenants with the Landlord pursuant to sub-
          clause 4.10  and

     (b)  in the case of an individual his personal representatives

          "Tenant" means the party described as the Tenant in the Particulars
and includes the Tenant's successors in title and assigns

          "Term" means the Contractual Term

          "Utilities" means water sewage gas electricity telephone
telecommunications and other services and supplies of whatever nature now or at
any time during the Term serving the Premises

          "Value Added Tax" means Value Added Tax or any other tax of a similar
nature that may be substituted for or levied in addition to it in each case at
the rate current from time to time

2.   INTERPRETATION
     --------------

     2.1. The Particulars and the Schedules form part of this Lease
<PAGE>
 
                                     - 8 -

     2.2. The definitions contained in the Particulars have the meanings
appearing alongside them for the purposes of this Lease

     2.3. Where the Landlord or the Tenant or the Surety for the time being are
two or more persons obligations expressed or implied to be made by or with such
party are deemed to be made by or with such persons jointly and severally

     2.4. Words importing one gender include all other genders and words
importing the singular include the plural and vice versa

     2.5.1.  Rights expressed to be reserved in favour of the Landlord shall be
deemed to extend to any superior landlord and any mortgagee of the Premises and
all persons authorised by the Landlord and by any superior landlord or mortgagee
including its or their agents professional advisers contractors and workmen

     2.5.2.  Rights expressed to be granted in favour of the Tenant shall be
deemed to extend to all persons authorised by the Tenant or its mortgagee
including its or their agents professional advisers contractors and workman

     2.6. Any covenants by the Tenant not to do an act or thing shall be deemed
to include an obligation not to permit or suffer such act or thing to be done

     2.7. Any provisions in this Lease referring to the consent or approval of
the Landlord shall be construed as also requiring the consent or approval of any
superior landlord where such consent shall be required but nothing in this Lease
shall be construed as implying that any obligation is imposed upon any superior
landlord not unreasonably to refuse or delay any such consent or approval

     2.8. Any references to a specific statute include any statutory extension
or modification amendment or re-enactment of such statute and any regulations
instruments or orders made under such statute and any general reference to
"statute" or "statutes" include any regulations instruments or orders made under
such statute or statutes

     2.9. References in this Lease to any Clause sub-clause Schedule or
paragraph without further designation shall be construed as a reference to a
Clause sub-clause or paragraph of or Schedule to this Lease so numbered
<PAGE>
 
                                     - 9 -

     2.10.  The Clause Paragraph and Schedule headings and the table of contents
are for ease of reference only and shall not be taken into account in the
construction or interpretation of this Lease or of the Clause Paragraph or
Schedule to which they refer

     2.11.  Any reference to a superior landlord includes the Landlord's
reversioner (whether mediate or immediate) at any time

     2.12.  References to "last year of the Term" include the last year of the
Term if the Term shall determine otherwise than by effluxion of time and
references to "expiry of the Term" include such other determination of the Term

     2.13.  The terms "parties" or "party" mean the Landlord and (or) the Tenant
and except where there is an express indication to the contrary include the
Surety

3.   DEMISE
     ------

     The Landlord at the request of the Surety demises to the Tenant the
Premises  TOGETHER WITH  the rights and easements set out in Part 1 of the First
Schedule but  EXCEPTING AND RESERVING  the rights and easements set out in Part
2 of the First Schedule  TO HOLD  the Premises to the Tenant for the Contractual
Term  YIELDING AND PAYING  to the Landlord:-

     3.1     on and from the date hereof until the Review Date the Principal
             Rent payable without any deduction by equal quarterly payments in
             advance on the usual quarter days the first such payment being a
             sum in respect of the period from and including the date hereof up
             to and including the day before the first quarter day after the
             date hereof and to be paid on the date hereof and

     3.2.    by way of further rent:-

     3.2.1.  the Insurance Rent payable at the times and in the manner provided
             in Clause 6

     3.2.2.  the payments of Interest referred to in sub-clause 4.18

     3.2.3.  the Service Charge payable at the times and in the manner provided
             in Clauses 1(2) 1(3) 1(4) 1(5) and 1(6) of the Superior Lease
<PAGE>
 
                                     - 10 -

4.   THE TENANT'S COVENANTS
     ----------------------

     The Tenant covenants with the Landlord throughout the Term:-

     4.1. Rents
          -----

          To pay the Rents on the days and in the manner set out or referred to
in this Lease and not to exercise or seek to exercise any right or claim to
withhold rent or any right or claim to legal or equitable set-off

     4.2. Outgoings and VAT
          -----------------

   4.2.1. To pay and to indemnify the Landlord against all rates taxes
          assessments duties charges impositions and outgoings which are now or
          during the Term shall be charged assessed or imposed upon the Premises
          or upon the owner or occupier of them save and except:

          (a)  any tax charged on the Landlord in respect of rents and other
               payments due under this Lease
          
          (b)  any tax occasioned by any disposition or deemed disposition of
               or dealing with the reversion expectant on the Term
          
          (c)  such rates taxes charges assessments duties impositions and
               outgoings as the Landlord is bound by law to pay
               notwithstanding any contract to the contrary

   4.2.2. To pay and to indemnify the Landlord against Value Added Tax
          chargeable in respect of any taxable supplies made to the Tenant by
          the Landlord under any of the terms of or in connection with this
          Lease (whether or not at the Landlord's election or otherwise
          howsoever arising) or in respect of any taxable supplies made by any
          third party to the Landlord where the Tenant agrees in this Lease to
          reimburse the Landlord for its costs in relation to those supplies and
          such sums shall be deemed to be and shall be recoverable as rent in
          arrear

   4.2.3. To pay and to indemnify the Landlord for all charges including meter
          rents for all Utilities consumed or used at or in relation to the
          Premises
<PAGE>
 
                                     - 11 -

     4.3.    Repair, cleaning and decorating
             -------------------------------

     4.3.1.  To keep the Premises in good and substantial repair and condition
             (damage or destruction caused by any of the Insured Risks excepted
             unless and to the extent that the insurance effected by the
             Landlord is vitiated forfeited or avoided or the insurance money is
             irrecoverable in consequence of any act or default of the Tenant or
             any person deriving title under the Tenant or anyone at the
             Premises expressly or by implication with the authority of the
             Tenant or such person)

     4.3.2.  To replace from time to time with items of an equivalent standard
             and commensurate with the nature of the Premises the Landlord's
             fixtures and fittings in the Premises which may be or become beyond
             repair at any time during or at the expiry of the Term

     4.3.3.  In each of the Interior Decorating Years and in the last year of
             the Term to redecorate the interior of the Premises in a good and
             workmanlike manner and with appropriate materials of good quality
             to the reasonable satisfaction of the Landlord

     4.3.4.  As often as may be necessary throughout the Term to clean and treat
             and wash in accordance with good standards and in a good and
             workmanlike manner to the reasonable satisfaction of the Landlord
             all materials surfaces and finishes of the interior of the Premises
             which ought normally to be so cleaned treated or washed (subject to
             the provisions of paragraph 4.3.5 below)

     4.3.5.  As often as may be reasonably necessary but no less frequently than
             once in every month of the Term to clean the internal surfaces of
             the glazing of the windows and other glazing which form part of the
             external envelope of the Building or which separate the Premises
             from any atria within the Building

     4.3.6.  Not to maintain repair replace or carry out any other works to or
             otherwise interfere with or damage any plant machinery apparatus
             and equipment relating to or connected with the air conditioning
             and heating systems

     4.3.7.  To comply in all respects with all reasonable regulations and
             requirements of or imposed by or on behalf of the Landlord in
             relation to the collection and disposal of refuse from the Premises
             and (or) from the Building
<PAGE>
 
                                     - 12 -

     4.4.    User and Restrictions on Use
             ----------------------------

     4.4.1.  Not to use the Premises for any purpose other than the Permitted
             User

     4.4.2.  Not to keep or use or permit or suffer to be kept or used on the
             Premises any materials of a dangerous inflammable or explosive
             nature or any machinery engine safe or other thing which may attack
             or in any way injure by percolation corrosion vibration excessive
             eight or otherwise the structure of the demised premises or the
             keeping or using whereof may contravene any statute or any local
             regulation or bye-law for the time being affecting the demised
             premises Provided that the Tenant may keep and use on the Premises
             inflammable materials used in the normal course of using premises
             as an office in such reasonable quantities only as may be necessary
             in connection with such use and subject to observing all statutes
             regulations and bye-laws relating to the keeping and using of such
             substances and complying with the requirements of the insurers of
             the Premises

     4.4.3.  Not to use the Premises for a sale by auction

     4.4.4.  Not to overload the existing electric wires and cables and in the
             event of any additional or new wiring or cable becoming necessary
             or of the Landlord being required by the Electricity Authority or
             by the Insurers or the Building to provide the same the Tenant
             shall pay the cost of all such additional or new wiring or cable
             exclusively used by the Premises and of connecting the same to the
             mains and a proportional part of the cost of any such wiring or
             cable in respect of those parts of the Building used in common with
             other tenants such proportion to be certified by the Landlord

   4.4.5.1.     Not to use or permit or suffer the Premises or any part thereof
                to be used for any illegal or immoral purpose nor for the
                manufacture sale or consumption on the premises of beer wine or
                spirituous liquors nor as a school consular or diplomatic office
                hotel club billiard-saloon restaurant snack-bar launderette sex-
                shop betting shop or office gaming house bingo-hall discotheque
                dance-hall funfair leisure-centre or amusement arcade nor for
                the business of an undertaker nor for any noisy noxious or
                offensive trade or business nor as a residence or sleeping place
                for any person nor for any purpose which would constitute a
                breach of any restrictive covenants affecting the Building
                Provided that such prohibitions shall not prevent the use of the
                Premises for instruction and lecture purposes
<PAGE>
 
                                     - 13 -

                and for a restaurant and snack-bar in each case as ancillary to
                the Tenant's use of the Premises

   4.4.5.2.     Not to do or permit or suffer to be done on the demised premises
                or any part thereof or in any communal part of the Building or
                the curtilage thereof anything which may be or become or cause a
                nuisance damage disturbance injury or danger of or to the
                Landlord or any other tenants of the Building or the owners
                lessees or occupiers of any premises in the neighbourhood and
                (without prejudice to the generality of the foregoing) not to
                use or permit or suffer to be used on the demised premises any
                electrical instrument or device unless fitted with an effective
                suppressor and properly earthed and insulated And to keep the
                Landlord fully and effectually indemnified against all actions
                proceedings damages costs expenses claims and demands whatsoever
                arising out of or in consequence of any breach or non-observance
                of this covenant

       4.5.  Waste and Alterations
             ---------------------

             Not to:-

     4.5.1.  commit any waste on or at the Premises

     4.5.2.  make any addition or extension to the Premises

     4.5.3.  unite the Premises with any adjoining premises

     4.5.4.  make any structural alteration to the Premises or

     4.5.5.  make any other alterations to the Premises PROVIDED THAT no consent
             shall be necessary for the erection removal and alteration of dry
             movable partitions within the Premises subject to the Tenant
             supplying full specifications and drawings within 7 days of
             completing such works and complying with all necessary statutory
             and other regulations whether relating to fire precautions or
             otherwise and preserving the integrity and proper working of the
             heating/air conditioning system for the Building and the Premises
             in particular and subject to the Tenant if so required by the
             Landlord removing the same at the end of the term and making good
             all damage thereby occasioned and restoring the demised premises to
             their former state and condition in all respects to the reasonable
             satisfaction of the Landlord and PROVIDED FURTHER THAT if in the
<PAGE>
 
                                     - 14 -

          Landlord's opinion any partitioning fails to comply with such
          regulations as aforesaid or interferes with or damages the said
          heating/air conditioning system for the Building the Tenant shall at
          the request of the Landlord remove the same and make good all damage
          thereby occasioned without delay

     4.6. Aerials Signs and Advertisements
          --------------------------------

          Not at any time to affix or exhibit or permit or suffer to be affixed
          or exhibited to or upon any part of the exterior of the Premises or on
          the inside surface of any windows of the Premises or elsewhere in the
          Building any placard poster sign signboard notice or advertisement
          except as permitted by the Regulations set out in the Fourth Schedule
          substituted therefor by the Superior Landlord for the good management
          and reputation of the said Building

     4.7. Obstruction
          -----------

          Not to do anything whereby any road path forecourt or other area over
          which the Tenant may have rights of access or use may be damaged or
          the proper use thereof by others may be obstructed in any way

     4.8. Statutory Obligations and Fire Precautions
          ------------------------------------------

  4.8.1.  At the Tenant's own expense to execute all works and provide and
          maintain all arrangements upon or in respect of the Premises or the
          use to which the Premises are being put that are required in order to
          comply with the requirements of any statute or any government
          department local authority other public or competent authority
          environmental authority or court of competent jurisdiction regardless
          of whether such requirements are imposed on the Landlord the Tenant or
          the occupier and where such works or arrangements are required in
          respect of the Premises and other parts of the Building to be carried
          out by the Landlord to pay to the Landlord on demand a contribution
          representing a proper and reasonable proportion of the cost of
          implementing such works or arrangements

  4.8.2.  At the Tenant's own expense and without limiting the obligations set
          out earlier in this sub-clause 4.8:-
<PAGE>
 
                                     - 15 -

     4.8.2.1.  to comply in all respects with the provisions of any statutes and
               any other obligations imposed by law or by any bye-laws
               applicable to the Premises or in regard to carrying on the
               business for the time being carried on at the Premises and

     4.8.2.2.  to comply with the requirements and recommendations of the fire
               authority and the Landlord in relation to fire precautions
               affecting the Demised Premises

     4.9.    Access to Landlord and Notice of Repair
             ---------------------------------------

     4.9.1.  To permit the Landlord on reasonable prior notice (except in case
             of emergency in which case no notice shall be necessary) and during
             reasonable times (or at any time in case of emergency):-

     4.9.1.1.  to enter upon the Premises for the purpose of ascertaining that
               the covenants and conditions of this Lease have been observed and
               performed

     4.9.1.2.  to inspect the state of repair and condition of the Premises

     4.9.1.3.  to give to the Tenant or leave upon the Premises a notice
               specifying any breach by the Tenant of the terms of this Lease
               and requesting the Tenant as soon as practicable to remedy the
               same and

     4.9.1.4.  to exercise the rights and easements excepted and reserved in
               Part 2 of the First Schedule

     4.9.2.  As soon as practicable to remedy the breach as required by such
             notice

     4.9.3.  If within ten Business Days (or within such shorter period as the
             Landlord may reasonably specify) of the service of such a notice
             the Tenant shall not have commenced and be proceeding diligently
             with the execution of the work referred to in the notice or shall
             have failed to complete the work within a reasonable period of time
             or if in the Landlord's reasonable opinion the Tenant is unlikely
             to have completed the work within such period to permit the
             Landlord to enter the Premises to execute such work as may be
             necessary to comply with the notice and to pay to the Landlord the
             proper cost of so doing and all proper expenses incurred by the
             Landlord (including legal costs and surveyor's fees) within ten
             Business Days of a written demand
<PAGE>
 
                                     - 16 -

     4.10.  Dealings
            --------

     4.10.1.  Not to:-
              
     4.10.1.1.       hold the Premises expressly or impliedly on trust for
                     another person
                    
     4.10.1.2.       part with possession of the Premises
                  
     4.10.1.3.       share possession of the Premises with another person
                  
     4.10.1.4.       allow anyone other than the Tenant its officers and
                     employees to occupy the Premises
                    
     4.10.2.  Not to assign a part (as distinct from the whole) of the Premises

     4.10.3.  Not to assign the whole of the Premises:-

     4.10.3.1.       unless the proposed assignee has first covenanted by deed
                     with the Landlord in such form as the Landlord may
                     reasonably require that with effect from the date of the
                     assignment and for the remainder of the Term the assignee
                     will pay the Rents and observe and perform all the
                     provisions of this Lease to be observed and performed by
                     the Tenant nor
                 
     4.10.3.2.       (where the proposed assignee is a corporate body and the
                     Landlord reasonably so requires) without first procuring
                     either covenants by deed in the form (mutatis mutandis)
                     ------
                     set out in the Third Schedule with the Landlord from not
                     less than two individuals who are or a corporate body which
                     is acceptable to the Landlord as guarantor or some other
                                                                --
                     form of collateral security reasonably acceptable to the
                     Landlord nor

     4.10.3.3.       without the prior written consent of the Landlord (which
                     will not be unreasonably withheld)
                 
     4.10.3.4.       The Tenant and the Surety shall be released from their
                     respective obligations contained in this Lease upon any
                     assignment of this Lease on the date two years after the
                     assignment has been completed

     4.10.4.  Not to charge a part (as distinct from the whole) of the Premises
<PAGE>
 
                                     - 17 -

     4.10.5.  Not to charge the whole of the Premises except to a bank or
              similar financial institution for the purpose only of borrowing
              money on the security of the Lease and with the prior written
              consent of the Landlord (which will not be unreasonably withheld)

     4.10.6.  Not to underlet a part (as distinct from the whole) of the
              Premises

     4.10.7.  Not to underlet the whole of the Premises:-

     4.10.7.1.  unless the proposed undertenant has first covenanted by deed
                with the Landlord in such form as the Landlord may reasonably
                require that with effect from the date of the underlease and
                during the term of the underlease the undertenant will observe
                and perform all the provisions of the underlease to be observed
                and performed by the undertenant and the provisions of this
                Lease (other than payment of the Principal Rent) to be observed
                and performed by the Tenant nor

     4.10.7.2.  (where the proposed undertenant is a corporate body and the
                Landlord reasonably so requires) without first procuring either
                                                                         ------
                covenants by deed with the Landlord in the form (mutatis
                mutandis) set out in the Third Schedule from two individuals who
                are or a corporate body which is acceptable to the Landlord as
                guarantor or an alternative form of security reasonably
                          --                                           
                acceptable to the Landlord nor

     4.10.7.3.  except by way of a Permitted Underlease nor

     4.10.7.4.  without the prior written consent of the Landlord (which will
                not be unreasonably withheld)

     4.10.8.  To enforce and not to waive or vary the provisions of a Permitted
              Underlease and to operate at the relevant dates of review the rent
              review provisions contained in an underlease but not to agree the
              rent upon such a review without the prior written approval of the
              Landlord

     4.10.9.  Within fifteen Business Days of any assignment charge underlease
              or sub-underlease or any transmission or other devolution relating
              to the Premises to give written notice thereof to the Landlord's
              solicitors together with three certified copies of the relevant
              document and to pay the Landlord's and Superior Landlord's
              solicitors' reasonable charges for the registration of every such
              document plus Value Added Tax
<PAGE>
 
                                     - 18 -

     4.11.  Landlord's Costs
            ----------------

            To pay to the Landlord and indemnify the Landlord against all
reasonable and proper costs fees charges disbursements and expenses on an
indemnity basis (including without prejudice to the generality of the above
those payable to counsel solicitors surveyors and bailiffs) reasonably and
properly incurred by the Landlord in relation to or incidental to:-

     4.11.1. every application made by the Tenant for a consent approval or
             licence required by the provisions of this Lease whether such
             consent approval or licence is granted or lawfully refused or
             proffered subject to any lawful qualification or condition or
             whether the application is withdrawn

     4.11.2. the preparation and service of a notice under Section 146 of the
             Law of Property Act 1925 or incurred by or in contemplation of
             proceedings under Sections 146 or 147 of that Act notwithstanding
             that forfeiture is avoided otherwise than by relief granted by the
             Court

     4.11.3. the recovery or attempted recovery of arrears of the Rents or
             other sums due from the Tenant and

     4.11.4. any steps taken in contemplation of or in connection with the
             preparation and service of a schedule of dilapidations during or
             after the expiry of the Term but which relates to dilapidations
             caused or occurring during the Term

     4.12.   The Planning Acts
             -----------------

     4.12.1. Not to commit any breach of the Planning Acts and to comply with
             the provisions and requirements of the Planning Acts that affect
             the Premises whether as to the Permitted User or otherwise and to
             indemnify and keep the Landlord indemnified both during and after
             the expiry of the Term against all liability whatsoever including
             costs and expenses incurred as a result of any breach occurring
             during the Term

     4.12.2. At the expense of the Tenant to obtain all planning permissions and
             to serve all such notices as may be required for the carrying out
             of any operations or user on the Premises which may constitute
             Development provided that no application for planning permission
             shall be made without the prior written consent of the Landlord
             such consent to be withheld or granted at the Landlord's absolute
             discretion provided that the Landlord shall not unreasonably
             withhold consent in relation to matters in respect of which it has
             already granted consent pursuant to sub-clause 4.5 unless the
<PAGE>
 
                                     - 19 -

             implementation of such planning permission would or would be likely
             to create or give rise to any tax or other fiscal liability for the
             Landlord and the Tenant fails to indemnify the Landlord against
             such liability having first been asked in writing to do so

     4.12.3. Subject only to any statutory direction to the contrary to pay and
             satisfy any charge or levy that may subsequently be imposed under
             the Planning Acts in respect of the carrying out or maintenance of
             any such operations or the commencement or continuance of any such
             user

     4.12.4. Notwithstanding any consent which may be granted by the Landlord
             under this Lease not to carry out or make any alteration or
             addition to the Premises or any change of use until:-

     4.12.4.1.  all necessary notices under the Planning Acts have been served
                and copies produced to the Landlord

     4.12.4.2.  all necessary permissions and consents under or pursuant to the
                Planning Acts have been obtained and produced to the Landlord
                and

     4.12.4.3.  the Landlord has acknowledged that every necessary planning
                permission is acceptable to it the Landlord being entitled to
                refuse to acknowledge its acceptance of a planning permission on
                the grounds that any condition contained in it or anything
                omitted from it or any period referred to in it would be or be
                likely to be prejudicial to the Landlord's interest in the
                Premises whether during or after the expiry of the Term

     4.12.5. Unless the Landlord shall otherwise direct to carry out and
             complete before the expiry of the Term:-

     4.12.5.1.  any works stipulated to be carried out to the Premises by a date
                subsequent to such expiry as a condition of any planning
                permission granted for any Development commenced before the
                expiry of the Term and

     4.12.5.2.  any Development commenced upon the Premises in respect of which
                the Landlord shall or may be or become liable for any charge or
                levy under the Planning Acts
<PAGE>
 
                                     - 20 -

     4.12.6. If required by the Landlord but at the cost of the Tenant to appeal
             against any refusal of planning permission or the imposition of any
             conditions on a planning permission relating to the Premises
             following an application by the Tenant

     4.12.7. Not to object to any application for planning permission that the
             Landlord may make whether jointly or alone in respect of any
             adjoining or neighbouring property

     4.13.   Plans, Documents and Information
             --------------------------------

             If reasonably called upon to do so to produce within a reasonable
             period of demand:

     4.13.1. to the Landlord all such plans documents and other evidence as the
             Landlord may reasonably require in order to satisfy itself that the
             provisions of this Lease have been complied with

     4.13.2. to the Landlord or its agent full particulars of all occupants of
             the Premises and the terms of their occupation

     4.14.   Indemnities
             -----------

             To be responsible for and to keep the Landlord fully indemnified
against all damage damages losses costs expenses actions demands proceedings
claims and liabilities made against or suffered or incurred by the Landlord and
for and against all damage occasioned to the Premises or to any other part of
the Building or any adjoining or neighbouring building arising directly or
indirectly out of:-

     4.14.1. any act omission or negligence of the Tenant or any persons at the
             Premises expressly or impliedly with the Tenant's authority or

     4.14.2. any breach or non-observance by the Tenant of the covenants
             conditions or other provisions of this Lease or any of the matters
             to which this demise is subject

     4.15.   Disposal Boards and Viewing
             ---------------------------

             To permit the Landlord upon reasonable notice and during the last
six months of the Contractual Term and at any time thereafter to permit upon
reasonable notice persons with the written authority of the Landlord
<PAGE>
 
                                     - 21 -

or its agent at reasonable times of the day to view the Premises without
interruption provided they are accompanied by the Landlord or its agents

     4.16.   Encroachments
             -------------

             Not to stop up darken or obstruct any windows or light belonging to
             the Premises.

     4.17.   Yield Up
             --------

             At the expiry of the Term:-

     4.17.1. to yield up the Premises in accordance with the terms of this
             Lease to the reasonable satisfaction of the Landlord

     4.17.2. to remove all placards signs notices fascias boards name-plates and
             advertisements fixed or exhibited by the Tenant in or upon the
             Premises and immediately to make good to the reasonable
             satisfaction of the Landlord any damage caused by such removal and

     4.17.3. to give up all keys of the Premises to the Landlord

     4.18.   Interest on Arrears
             -------------------

             If the Tenant shall fail to pay the Rents or any other sum due
under or pursuant to this Lease within ten Business Days of the date on which
payment was due and formally demanded (except in the case of the Principal Rent)
the Tenant shall pay to the Landlord Interest on the Rents or other such sum and
such Interest shall be deemed to be and shall be recoverable as rent in arrear

     4.19.  Statutory Notices
            -----------------

            To give full particulars to the Landlord of any notice direction
order or proposal for the Premises made given or issued to the Tenant by any
local or public authority within three Business Days of receipt and if so
required by the Landlord to produce it to the Landlord and without delay and at
the cost of the Tenant to take all necessary steps to comply with such notice
direction or order
<PAGE>
 
                                     - 22 -

     4.20.   Defective Premises
             ------------------

             To give notice to the Landlord of any defect in the Premises which
might give rise to an obligation on the Landlord to do or refrain from doing any
act or thing in order to comply with the provisions of this Lease or the duty of
care imposed on the Landlord pursuant to the Defective Premises Act 1972 or
otherwise and at all times to display and maintain all necessary notices which
the Landlord may from time to time require to be displayed at the Premises

     4.21.   Compliance with Regulations
             ---------------------------

             At all times during the term to observe perform and comply with the
conditions and regulations specified in the Fourth Schedule hereto and any
alterations or additions thereto which may from time to time be made by the
Landlord for the good management and reputation of the Building and the
curtilage thereof and the parking areas or the safety or convenience of the
tenants thereof And to take all reasonable steps to secure compliance with such
conditions and regulations by the Tenant's staff and visitors

     4.22.   Outside Business Hours
             ----------------------

             To give to the Landlord reasonable prior notice if the Tenant
wishes to have access to the Premises outside the Business Hours for the
Building and to pay to the Landlord on demand from time to time the costs of
providing any of the services requited by the Tenant outside the Business Hours

     4.23.   Superior Lease Covenants
             ------------------------

     4.23.1. To observe and perform the Superior Lease Covenants

     4.23.2. Not to do or permit or suffer anything whereby the Superior Lease
             may be avoided or forfeited

     4.23.3. To keep the Landlord indemnified against all claims liabilities
             costs and expenses for or in respect of any breach by the Tenant of
             the Superior Lease Covenants

     4.23.4. To permit the Landlord and any authorised person to enter the
             Premises at reasonable times only and upon reasonable prior notice
             (except in cases of emergency) in order to comply with any of the
             Superior Lease Covenants which may be necessary to prevent a
             forfeiture of the Superior Lease subject to the Landlord making
             good without unreasonable delay any damage thereby caused
<PAGE>
 
                                     - 23 -

     4.24.  Option to Determine
            -------------------

            If the Tenant shall desire to terminate the Term and to quit the
Premises on the date of expiry of the fifth year of the Term and shall give to
the Landlord not less than twelve months previous notice in writing to that
effect (in respect of which notice time shall be of the essence) then upon the
expiration of such notice the term of years created by this underlease shall
forthwith cease and determine but without prejudice to any remedy of either
party against the other in respect of any antecedent claims or breach of
covenant contained in this Lease and the Tenant shall deliver up vacant
possession of the Premises

5.   THE LANDLORD'S COVENANTS
     ------------------------

     The Landlord covenants with the Tenant that:-

     5.1.   the Tenant paying the Rents and performing and observing the
            covenants and conditions on the part of the Tenant herein contained
            the Landlord shall permit the Tenant peaceably and quietly to hold
            and enjoy the Premises during the Term without any interruption or
            disturbance from or by the Landlord or by any person lawfully
            claiming through under or in trust for the Landlord

     5.2.   it will use best endeavours to procure the compliance by the
            Superior Landlord with the covenants on the part of the Superior
            Landlord contained in the Superior Lease

     5.3.   the Landlord shall during the Term pay the rent reserved by the
            Superior Lease and perform and observe the covenants and conditions
            contained in the Superior Lease and on the part of the Landlord as
            tenant to be performed and observed except to the extent that they
            fall to be performed and observed by the Tenant pursuant to this
            Lease

6.   INSURANCE
     ---------

     6.1.   Tenant's Insurance Covenants
            ----------------------------

            The Tenant covenants with the Landlord:-

     6.1.1. to pay the Insurance Rent within ten business days of a written
            demand for the period from and including the date of this Lease up
            to and including the day before the next policy renewal date and
            subsequently to pay the Insurance Rent within ten Business Days of a
            written demand and (if
<PAGE>
 
                                     - 24 -

            so demanded) in advance of the policy renewal date provided that any
            such demand will be supported by proper evidence that the demand has
            been properly made

     6.1.2. to comply with all the requirements and recommendations of the
            insurers of the Building that are notified to the Tenant

     6.1.3. not to do or knowingly permit anything that could cause any policy
            of insurance on or in relation to the Building to become void or
            voidable wholly or in part nor (unless the Tenant shall have
            previously notified the Landlord and agreed to pay the increased
            premium) anything by which additional insurance premiums may become
            payable

     6.1.4. to keep the Premises supplied with such fire fighting equipment as
            the insurer may require or as the Landlord may reasonably require
            and to maintain such equipment to their satisfaction and in
            efficient working order

     6.1.5. to comply with the requirements and recommendations of the insurer
            and the reasonable requirements of the Landlord as to fire
            precautions relating to the Premises

     6.1.6. not to obstruct the access to any fire equipment or the means of
            escape from the Premises nor to lock any fire door while the
            Premises are occupied

     6.1.7. as soon as it reasonably comes to the attention of the Tenant to
            give notice to the Landlord immediately upon the happening of any
            event which might affect any insurance policy on or relating to the
            Premises or upon the happening of any event against which the
            Landlord may have insured under this Lease

     6.1.8. not to effect any policy of insurance in relation to the Building
            without the prior written consent of the Landlord PROVIDED THAT the
            Tenant may insure the contents of the Premises and third party risks
            without the consent of the Landlord

     6.1.9. if at any time the Tenant shall be entitled to the benefit of any
            insurance on the Premises except insurance of the contents of the
            Premises and third party risks (which is not effected or maintained
            in pursuance of any obligation contained in this Lease) to apply all
            money received by virtue of such insurance in making good the loss
            or damage in respect of which such money shall have been received
<PAGE>
 
                                     - 25 -

     6.1.10. if and whenever during the Term the Premises or any part ("the
             relevant part") of the Building giving access to the Premises are
             damaged or destroyed by any of the Insured Risks and the insurance
             money under the policy of insurance effected by the Landlord
             pursuant to its obligations contained in this Lease is by reason of
             any act or default of the Tenant or anyone at the Premises
             expressly or by implication with the Tenant's authority wholly or
             partially irrecoverable immediately in every such case to pay to
             the Landlord on demand the amount of such insurance money so
             irrecoverable with Interest on such amount (from the date of demand
             or (if earlier) the date on which the Landlord first suffered
             financial loss because of the insurance money being irrecoverable
             in whole or in part as aforesaid)

     6.2.    Suspension of Principal Rent
             ----------------------------

             That if the Premises or any part thereof shall at any time during
the term be destroyed or damaged by any of the Insured Risks so as to be unfit
for occupation and use and any policy or policies of insurance effected by the
Landlord shall not have vitiated or payment of the policy monies refused in
consequence of some act or default of the Tenant the rents hereby reserved shall
be suspended and shall cease to be payable until the Premises shall again be
rendered fit for occupation and use or until the expiration of a period of three
years (whichever shall be the shorter period) and if the Premises are not
reinstated or rebuilt within the period of three years the Tenant may terminate
this Lease by giving written notice to the Landlord within one month after the
expiration of the period of three years and upon service of such notice this
Lease shall terminate but without prejudice to any claim the Landlord may have
against the Tenant for any earlier breach of covenant and any dispute concerning
this Clause shall be determined by a single arbitrator in accordance with the
Arbitration Acts 1950 and 1979

7.   PROVISOS
     --------

     7.1. Re-Entry
          --------

          If and whenever during the Term:-

          7.1.1.  the Rents (or any of them or any part of them) under this
                  Lease are outstanding for more than ten Business Days after
                  becoming due whether formally demanded or not or

          7.1.2.  there is a breach by the Tenant or the Surety of any covenant
                  or other term of this Lease or any document expressed to be
                  supplemental to this Lease or
<PAGE>
 
                                     - 26 -

          7.1.3.  the Tenant or the Surety commits or permits an Act of
                  Insolvency

          the Landlord may re-enter the Premises or any part of them in the name
          of the whole at any time and even if any previous right of re-entry
          has been waived and then the Term will absolutely cease but without
          prejudice to any rights or remedies which may have accrued to the
          Landlord against the Tenant or the Surety in respect of any breach of
          covenant or other term of this Lease including the breach in respect
          of which the re-entry is made

     7.2. Rights and Easements
          --------------------

          The operation of Section 62 of the Law of Property Act 1925 shall be
excluded from this Lease and the only rights granted to the Tenant are those
expressly set out in Part I of the First Schedule and the Tenant shall not by
virtue of this Lease be deemed to have acquired or be entitled to and the Tenant
shall not during the Term acquire or become entitled to by any means whatever
any easement from or over or affecting any other land or premises now or at any
time after the date of this Lease belonging to the Landlord or any Group Company
of the Landlord and not comprised in this Lease

     7.3. Disputes with Adjoining Occupiers
          ---------------------------------

          If any dispute arises between the Tenant and the tenants or occupiers
of other parts of the Building or the Adjoining Property as to any easement
right or privilege in connection with the use of the Premises and any other part
of the Building or the Adjoining Property or as to the boundary structures
separating the Premises from any other property it shall be decided by the
Landlord or in such manner as the Landlord shall direct

     7.4. Exclusion of Use Warranty
          -------------------------

          Nothing in this Lease or in any consent granted by the Landlord under
this Lease shall imply or warrant that the Premises may lawfully be used under
the Planning Acts for the purpose authorised in this Lease or any purpose
subsequently authorised

     7.5. Representations
          ---------------

          The Tenant acknowledges that this Lease has not been entered into in
reliance wholly or partly on any statement or representation made by or on
behalf of the Landlord except any such statement or representation that is
expressly set out in this Lease and those contained in the Replies to
Preliminary Enquiries
<PAGE>
 
                                     - 27 -

     7.6.  Tenant's Property
           -----------------

     If after the Tenant has vacated the Premises on the expiry of the Term any
property of the Tenant remains in or on the Premises and the Tenant fails to
remove it within ten Business Days after being requested in writing by the
Landlord to do so or if after using all reasonable endeavours the Landlord is
unable to make such a request to the Tenant within ten Business Days from the
first attempt so made by the Landlord:-

     7.6.1.  the Landlord may as the agent of the Tenant sell such property and
             the Tenant shall indemnify the Landlord against any liability
             incurred by it to any third party whose property shall have been
             sold by the Landlord in the mistaken belief held in good faith
             (which shall be presumed unless the contrary is proved) that such
             property belonged to the Tenant

     7.6.2.  the Landlord shall (subject to paragraph 7.6.3 below) forthwith
             after such sale pay to the Tenant the proceeds of such sale after
             having deducted the reasonable fees and expenses incurred by or on
             behalf of the Landlord in connection with such sale

     7.6.3.  if the Landlord having made reasonable efforts is unable to locate
             the Tenant the Landlord shall be entitled to retain such proceeds
             of sale absolutely unless the Tenant shall claim them within three
             months of the date on which the Tenant vacated the Premises and

     7.6.4.  the Tenant shall indemnify the Landlord against any damage
             occasioned to the Premises and any actions claims proceedings costs
             expenses and demands made against the Landlord caused by or related
             to the presence of the property in or on the Premises

     7.7.    Compensation on Vacating
             ------------------------

             Any statutory right of the Tenant to claim compensation from the
Landlord on vacating the Premises shall be excluded to the extent that the law
allows

     7.8.    Covenants Relating to Adjoining Premises
             ----------------------------------------

             Nothing contained in or implied by this Lease shall give the Tenant
the benefit of or the right to enforce or to prevent the release or
modifications of any covenant agreement or condition entered into by any tenant
of the Landlord in respect of any property not comprised in this Lease
<PAGE>
 
                                     - 28 -

     7.9.    Service of Notices
             ------------------

     7.9.1.  The provisions of Section 196 of the Law of Property Act 1925 as
             amended by the Recorded Delivery Service Act 1962 shall apply to
             the giving and service of all notices and documents under or in
             connection with this Lease except that Section 196 shall be deemed
             to be amended as follows:-

                the final words of Section 196(4)" . . . . and that service . .
                . be delivered" shall be deleted and there shall be substituted
                ". . . and that service shall be deemed to be made on the second
                Business Day after the registered letter has been posted"

     7.9.2.  Any notice or document shall also be sufficiently served if sent by
             telex facsimile transmission or any other means of electronic
             transmission to the party to be served and that service shall be
             deemed to be made on the day of transmission if transmitted before
             4 p.m. on a Business Day but otherwise on the next following
             Business Day

             and in this Clause "party" includes the Surety

     7.10.   Value Added Tax
             ---------------

     7.10.1. Save as the context requires or as otherwise stated all references
             to payments made in this Lease are references to such payments
             exclusive of any Value Added Tax chargeable in respect of the
             supply of goods or services for which the payment is consideration
             and insofar as such payments fall to be made under this Lease such
             Value Added Tax shall be added to the amount thereof and paid in
             addition thereto

     7.10.2. Without prejudice to and save as mentioned earlier in this sub-
             clause 7.10 where any supply is made pursuant to this Lease the
             recipient of such supply shall pay to the supplier any Value Added
             Tax chargeable in respect thereof

     7.10.3. Where any payment is required to be made pursuant to this Lease to
             reimburse the payee for any expenditure which the payee may have
             incurred such payment shall include an amount equal to any Value
             Added Tax comprised in that expenditure which is not recoverable by
             the payee as input tax under Section 14 of the Value Added Tax Act
             1983
<PAGE>
 
                                     - 29 -

     7.11.   Exclusion of Landlord and Tenant Act 1954
             -----------------------------------------

             Having been authorised to do so by Order of the Lambeth County
Court made on the 14th day of December 1993 under the provisions of Section
38(4) of the Landlord and Tenant Act (as amended by Section 5 of the Law of
Property Act 1969) the Landlord and the Tenant hereby agree that the provisions
of Section 24 to 28 (inclusive) of the Landlord and Tenant Act shall be excluded
in relation to this Lease

     7.12.   Jurisdiction
             ------------

     7.12.1. This Deed shall be governed by and construed in accordance with
             English Law

     7.12.2. The parties hereto irrevocably submit to the non-exclusive
             jurisdiction of the High Court of Justice in London for the purpose
             of hearing and determining any dispute arising out of this Deed and
             for the purpose of enforcement of any judgment against its assets
             the Surety agrees that service of any writ notice or other document
             for the purpose of any proceedings in such Court shall be duly
             served upon it if delivered or sent by registered post to ACC Corp
             at 39 State Street City Rochester NY 14614 United States of America

     IN WITNESS of which this Lease has been executed as a Deed by the parties
and is delivered on the date appearing in the Particulars

                               THE FIRST SCHEDULE
                               ------------------
                                     Part 1
                                     ------
                          Rights and Easements Granted
                          ----------------------------

1.   The exclusive right to park private motor cars in eight parking spaces in
the Car Park and/or any adjoining parking area from time to time available to
the Landlord

2.   The following rights (in common with the Landlord the Superior Landlord and
their lessees and tenants and all other persons expressly or impliedly
authorised by them respectively):-

     2.1. the right at all times to use the common entrance halls (including the
          approaches thereto from the public highway) staircases lift lobbies
          corridors passages toilets and (during the hours when the same shall
          be in operation) the lifts for the purpose of ingress to and egress
          from the Premises:-
<PAGE>
 
                                     - 30 -

          (i)  during the hours of 9.00 a.m. to 12.30 p.m. on Saturdays and 8.30
               a.m. to 6.30 p.m. on all other weekdays except Bank and other
               general Public Holidays

          (ii) subject to the Tenant complying with the covenant contained in
               Clause 4.22 during all other hours and days

     2.2. the free and uninterrupted passage and running of water soil gas
          electricity telephone telex air and other services from or to the
          Premises through the sewers drains pipes cables conduits and ducts
          which are now or may hereafter be in under over or upon the Building

     2.3. the right to support shelter and protection for the Premises from the
          remainder of the Building

                               THE FIRST SCHEDULE
                               ------------------
                                     Part 2
                                     ------
                   Rights and Easements Excepted and Reserved
                   ------------------------------------------

1.   The right at any time to alter or add to any adjoining adjacent or
neighbouring premises or building upon any adjoining adjacent or neighbouring
land or to build thereon notwithstanding that the access of light or air to any
windows of the Premises is thereby diminished but provided that any damage
caused in the exercise of such right is forthwith made good to the satisfaction
of the Tenant

2.   The free and uninterrupted passage and running of water soil gas
electricity telephone telex air and other services from or to other parts of the
Building through the sewers drains pipes wires cables conduits and ducts which
are now or may hereafter be in under over or upon the Premises

3.   The full and free right and liberty to enter upon the Premises after giving
the requisite notice (except in case of emergency or as otherwise provided) at
such times and for such purposes as the Tenant herein covenants to permit entry
or where the same is necessary for the purposes of enabling the Landlord to
comply with its obligations herein contained and perform the services set out in
the Fourth Schedule of the Superior Lease

4.   Full right of support shelter and protection for the remainder of the
Building from the Premises
<PAGE>
 
                                     - 31 -

                                 THE SECOND SCHEDULE
                                 -------------------
                         Principal Rent and Rent Review
                         ------------------------------

1.   In this Schedule the following expressions shall have the following
meanings:-

     (a)  "the Review Date" means the Twenty fifth day of December One thousand
          nine hundred and ninety eight

     (b)  "the rent periods" means the initial period commencing with the date
          on which rent commences to be payable hereunder until (but not
          including) the Review Date and thereafter the final period to the end
          of the term

     (c)  "the basic yearly rent" means the Principal Rent

     (d)  "commercial yearly rent" means the yearly rent at which the Premises
          as a whole might reasonably be expected then to be let in the open
          market with vacant possession by a willing landlord to a willing
          tenant by a lease in the same terms in all respects as this Lease
          (other than the amount of the basic yearly rent payable hereunder but
          including the provisions for rent review and excluding the provisions
          of Clause 4.24 of this Lease) for a term equal to the original term of
          this Lease commencing on the Review Date and on the following
          assumptions (whether or not such shall in fact be the case):-

          (i)  that  the  Premises  are  fitted  out  and   equipped   for
               immediate occupation and use for the purpose or purposes required
               by the willing tenant referred to in paragraph (d) above

         (ii)  that no work has been carried out thereon by the Tenant its sub-
               tenants or their respective predecessors in title during the
               Contractual Term which has diminished the rental value of the
               Premises and that in case the Premises have been destroyed or
               damaged they have been fully restored

        (iii)  that all the Tenant's covenants and conditions in this Lease
               have been duly performed and observed
<PAGE>
 
                                     - 32 -

         (iv)  that the Premises may be lawfully used by any person for the
               purposes permitted under this Lease

          (v)  that the willing tenant referred to in paragraph (d) would
               commence paying rent immediately on and from the Review Date and
               that such rent would not be discounted in any way to reflect any
               rent concession or other benefit

          but disregarding

          (i)  any effect on rent of the fact that the Tenant its sub-tenants or
               their respective predecessors in title have been in occupation of
               the Premises or any part thereof

         (ii)  any goodwill attached to the Premises or any part thereof by
               reason of the carrying on thereat of the business of the Tenant
               its sub-tenants or their predecessors in title in their
               respective businesses and

        (iii)  any effect on rent of any improvement of the Premises or any
               part thereof completed not more than twenty one years prior to
               the date at which the review is to take effect and carried out
               with consent (where required) otherwise than in pursuance of an
               obligation to the Landlord or its predecessors in title either
               (a) by the Tenant its sub-tenants or their respective
               predecessors in title during the term or (b) by any tenant or
               sub-tenant of the Premises before the commencement of the term so
               long as the Landlord or its predecessors in title have not since
               the improvement was carried out had vacant possession of the
               relevant part of the Premises

2.   The Landlord shall be entitled by notice in writing given to the Tenant at
any time during the last year of any rent period to call for a review of the
basic yearly rent payable under this Lease and if upon any such review it shall
be found that the commercial yearly rent of the Premises at the end of such rent
period shall be greater than the Principal Rent hereinbefore reserved then as
from the end of such rent period the basic yearly rent payable under this Lease
shall on each such occasion be increased to the then commercial yearly rent as
aforesaid

3.   If notwithstanding the provisions of the previous sub-clause a review of
the basic yearly rent shall not have been called for during the last year of any
rent period by notice as aforesaid the Landlord may at any time during the first
four years of the next rent period immediately following serve upon the Tenant a
notice calling for a review of the basic yearly rent payable under this Lease
and if upon any such review it shall be found that the commercial
<PAGE>
 
                                     - 33 -

yearly rent of the demised premises at the end of the year of the term in which
or at the next usual quarter day following the date on which the notice was
actually served (whichever shall be the earlier) shall be greater than the
Principal Rent hereinbefore reserved or than the basic yearly rent then payable
hereunder owing to the operation of this present Schedule (as the case may be)
then as from the end of such year of the term or such quarter day (whichever
shall be the earlier) the basic yearly rent payable under this Lease shall on
each such occasion be increased to the then commercial yearly rent as aforesaid
Provided always that:-

     (a)  a review of the basic yearly rent shall (except in circumstances
          arising under paragraph (b) of this proviso) only be called for once
          in accordance with the provisions of this sub-clause and the previous
          sub-clause of this Schedule during the period of five years commencing
          with the last year of each rent period  and

     (b)  if a review of the basic yearly rent shall have been called for at any
          time in accordance with this sub-clause or the previous sub-clause of
          this Schedule by notice as aforesaid but the right to review the basic
          yearly rent or to recover an increased basic yearly rent is restrained
          or restricted by or by virtue of any Act of Parliament coming into
          force after the review has been called for as aforesaid so that either
          the review cannot be carried out or the whole or any part of any
          increase in the basic yearly rent arising upon that review cannot be
          recovered with effect from the review date the Landlord may by notice
          in writing to the Tenant require the previous sub-clause or this sub-
          clause (as the case may be) to be construed as if the basic yearly
          rent was to be reviewed at and any increased basic yearly rent found
          to be payable was to be payable with effect from the date upon which
          such restraint or restriction was first removed or relaxed and for the
          purpose of operating the review procedure under sub-clause 4 of this
          Schedule such notice shall be construed as the Landlord's notice
          calling for review in lieu of the notice served by the Landlord under
          this sub-clause or the previous sub-clause of this Schedule (as the
          case may be)

4.   Such review shall in the first instance be made by the Landlord and the
Tenant or their respective Surveyors in collaboration but if no agreement as to
the amount of the increase (if any) to be made in the said yearly rent shall
have been reached between the parties within three months after the date of the
Landlord's notice calling for such review (or any extension of such time agreed
in writing between the parties) the question whether there shall be an increase
in the said yearly rent (and if so what the amount of the revised yearly rent
shall be) shall be determined by an arbitrator such arbitrator to be nominated
in the absence of agreement by or on behalf of the President for the time being
of the Royal Institution of Chartered Surveyors on the application of either the
Landlord or the Tenant  And in relation to the application for any such
nomination or the determination by the person nominated time shall not be of the
essence  Provided always that if at any review date the revised basic yearly
rent to be
<PAGE>
 
                                     - 34 -

payable as from such review date shall not then have been agreed between the
Landlord and the Tenant and if the parties shall not have made any application
to the President for the time being of the Royal Institution of Chartered
Surveyors as hereinbefore provided and shall not have agreed on the identity of
the arbitrator the Tenant may serve on the Landlord notice in writing containing
a proposal as to the amount of such revised basic yearly rent not being less
than the basic yearly rent payable immediately before such review date and the
amount so proposed shall be deemed to have been agreed by the parties as the
revised basic yearly rent to be payable from such review date and sub-clause 6
of this Schedule shall apply accordingly unless the Landlord shall make such
application as aforesaid within three months after service of such notice by the
Tenant

5.   (a)  In the case of an arbitration the arbitration shall be conducted in
accordance with the Arbitration Act 1950 to 1979

     (b)  When the amount of any basic yearly rent to be ascertained as
hereinbefore provided shall have been so ascertained memoranda specifying and
confirming the revised basic yearly rent to be payable shall forthwith be signed
by or on behalf of the Landlord and the Tenant and annexed to this Lease and the
Counterpart thereof and the parties shall bear their own costs in respect
thereof

6.   If at any review date the revised basic yearly rent to be payable as from
such review date shall not then have been agreed or determined in the manner
aforesaid then until such agreement or determination shall have been made the
Tenant shall pay the said rent at such yearly rate at such times and in such
manner as shall have been applicable immediately prior to such review date and
any rent in excess of such rent which may later be found to be payable hereunder
in respect of the period from such review date until the quarter day next
following such agreement or determination shall be paid without any deduction
within twenty one days of the date on which the revised basic yearly rent shall
have been ascertained with interest thereon at four per cent below the Interest
Rate calculated on a day to day basis from the date at which the rent was to be
reviewed down to the date of payment

                               THE THIRD SCHEDULE
                               ------------------
                            Covenants by the Surety
                            -----------------------

1.1. Covenant and indemnity by Surety
     --------------------------------

     (a) In consideration of the Landlord entering into this Lease the Surety
covenants with the Landlord that:-
<PAGE>
 
                                     - 35 -

     (i)  the Tenant (failing whom the Surety) will at all times during the Term
          duly perform and observe all the covenants on the part of the Tenant
          contained in this Lease (including without limitation the payment of
          the Rents and all other sums payable under this Lease) in the manner
          and at the times specified in this Lease  and

     (ii) the Surety will indemnify and keep indemnified the Landlord against
          all claims demands losses damages liability costs fees and expenses
          whatsoever sustained by the Landlord by reason of or arising in any
          way directly or indirectly out of any default by the Tenant in the
          performance and observance of any of its obligations hereunder or the
          payment of any Rents or other sums payable hereunder or arising as a
          result of the Lease being disclaimed by a liquidator or trustee in
          bankruptcy or similar officer appointed to or in respect of the Tenant
          and having such power (each a "Relevant Disclaimer")

     (b)  For the purposes of Clause 1.1(a) above the Term will be deemed to
continue for the duration specified in this Lease notwithstanding that a
Relevant Disclaimer occurs

1.2. Nature of Surety's Obligations
     ------------------------------

     (a) The obligations of the Surety hereunder are primary obligations

     (b) The Surety is jointly and severally liable with the Tenant for the
fulfillment of all the obligations of the Tenant under this Lease

     (c) Notwithstanding any legal limitation disability or incapacity on or of
the Tenant or any other fact or circumstance whether known to the Landlord or
not the Landlord may proceed against and recover from the Surety as if the
Surety was named as the Tenant in this Lease

     (d) The Landlord shall not be obliged to make any demand on the Tenant
before enforcing its rights against the Surety hereunder

1.3. Waiver by Surety
     ----------------

     The obligations of the Surety hereunder are to constitute a continuing
security in addition to and without prejudice to any other rights which the
Landlord may have and the Surety hereby waives any right to require the
<PAGE>
 
                                     - 36 -

Landlord to proceed against the Tenant or to pursue any other remedy whatsoever
which may be available to the Landlord before proceeding against the Surety

1.4. Postponement of claims by Surety against Tenant
     -----------------------------------------------

     (a) Unless otherwise instructed by the Landlord the Surety will not claim
or accept any payment or property in any liquidation bankruptcy composition or
arrangement of the Tenant in competition with the Landlord nor seek to recover
(whether directly or by way of set off lien counter claim or otherwise) any
money or other property nor exercise any other right or remedy whatsoever in
respect of any sum which may be or become due to the Surety from the Tenant nor
exercise any rights of subrogation or indemnity against the Tenant until in each
such case all the Surety's obligations hereunder have been performed and
discharged in full

     (b) The Surety will forthwith pay to the Landlord an amount equal to any
set-off in fact exercised by it and will promptly pay or transfer to the
Landlord any payment or distribution or benefit in fact received by it
notwithstanding the terms of Clause 1.4(a) above

     (c) The Surety agrees that it will exercise any rights of subrogation
against the Tenant and any rights to prove in a liquidation of the Tenant which
it may have in accordance with the directions of the Landlord

1.5. Postponement of participation by Surety in security
     ---------------------------------------------------

     The Surety confirms it has not taken and undertakes it will not take from
the Tenant any security in connection with its obligations hereunder and
declares that any security so taken shall be held on trust for the Landlord and
further the Surety agrees that it shall not be entitled to participate in any
security held by the Landlord in respect of the Tenant's obligations to the
Landlord under this Lease nor to stand in the place of the Landlord in respect
of any such security until all the obligations of the Tenant or the Surety to
the Landlord under this Lease have been performed or discharged in full

1.6. No release of Surety
     --------------------

     None of the following nor any combination thereof shall release determine
discharge or in any way lessen or affect the liability of the Surety hereunder
or otherwise prejudice or affect the right of the Landlord to recover from the
Surety to the full extent of its obligations hereunder:-
<PAGE>
 
                                     - 37 -

     (a)  any neglect delay or forbearance of the Landlord in endeavouring to
          obtain payment of the Rents or other amounts payable under this Lease
          by the Tenant or in enforcing the performance or observance of any of
          the obligations of the Tenant under this Lease

     (b)  any refusal by the Landlord to accept Rents tendered by or on behalf
          of the Tenant

     (c)  any extension of time given by the Landlord to the Tenant

     (d)  any variation of the terms of this Lease (including any reviews of the
          Principal Rent) or the transfer of the Landlord's reversion or the
          assignment of this Lease or the surrender of any part thereof

     (e)  the release of any person for the time being jointly or severally
          liable for the Tenant's obligations or liable as surety for the
          Tenant's obligations

     (f)  any change in the constitution structure or powers of any of the
          Tenant the Surety or the Landlord or the liquidation administration or
          bankruptcy (as the case may be) of any of the Tenant the Surety or the
          Landlord

     (g)  any legal limitation or any immunity disability or incapacity of the
          Tenant (whether or not known to the Landlord) or the fact that any
          dealings with the Landlord or the Tenant may be outside or in excess
          of the powers of the Tenant or the Surety

     (h)  the taking variation compromise renewal release or refusal or neglect
          to perfect or enforce any right remedies or securities against the
          Tenant or any other person

     (i)  any Relevant Disclaimer

     (j)  any other act omission matter or thing whatsoever whereby but for this
          provision the Surety would be exonerated or released either wholly or
          in part (other than a release by Deed given by the Landlord)

1.7. Disclaimer or forfeiture of Lease
     ---------------------------------

     (a)  The Surety undertakes to the Landlord that:-
<PAGE>
 
                                     - 38 -

          (i) if a liquidator or trustee in bankruptcy or similar officer having
              such power shall disclaim or surrender this Lease or

         (ii) if this Lease shall be forfeited or

        (iii) if the Tenant shall cease to have legal existence

THEN  the Surety shall if the Landlord by notice in writing given to the Surety
within six (6) months after such disclaimer or other event occurs so requires
accept from and execute and deliver to the Landlord a counterpart of a new lease
of the Premises for a term commencing on the date of the disclaimer or other
event and continuing for the residue then remaining unexpired of the Term (as
specified in this Lease) such new lease to be at the cost of the Surety and to
be at the same rents and subject to the same covenants conditions and provisions
as are contained in this Lease

     (b) If this Lease is disclaimed and for any reason the Landlord does not
require the Surety to accept a new lease of the Premises in accordance with this
Schedule the Landlord shall be entitled to require that the Surety pays to the
Landlord on demand an amount equal to the Rents for the period commencing with
the date of such disclaimer and ending on whichever is the earlier of:-

          (i)  the date six months after such disclaimer  and

          (ii) the date (if any) upon which the Premises are relet

1.8. Cumulative Powers and Avoidance of Payments
     -------------------------------------------

     (a) The powers conferred on the Landlord hereunder are cumulative without
prejudice to its powers under the general law and may be exercised as often as
the Landlord thinks appropriate  The Landlord may in connection with the
exercise of its powers join or concur with any person in any transaction scheme
or arrangement whatsoever

     (b) If the Landlord reasonably considers that any amount paid by the Surety
hereunder is capable of being avoided or set aside on the liquidation or
administration of the Surety or otherwise then for the purposes of this Lease
such amount shall not be considered to have been paid
<PAGE>
 
                                     - 39 -

     (c) Any settlement or discharge between the Landlord and the Tenant and/or
the Surety shall be conditional upon no security or payment to the Landlord by
the Tenant or the Surety or any other person being avoided or set aside or
ordered to be refunded or reduced by virtue of any provision or enactment
relating to bankruptcy insolvency or liquidation for the time being in force and
accordingly (but without limiting the Landlord's other rights hereunder) the
Landlord shall be entitled to recover from the Surety the value which the
Landlord has placed upon such security or the amount of any such payment as if
such settlement or discharge had not occurred

1.9.  Representations
      ---------------

      The Surety warrants and represents that it has full power to enter into
the obligations and covenants hereunder and has taken all necessary corporate or
other action required to authorise its execution of this Lease and that the
provisions of this Lease constitute the legal valid and binding obligations of
the Surety

1.10.  Benefit of guarantee
       --------------------

       (a) The covenants undertakings and agreements of the Surety hereunder
shall enure for the benefit of the successors and assigns of the Landlord to
this Lease without the necessity for any assignment thereof to such successors
and assigns

       (b) Without prejudice to Clause 1.10(a) above the Landlord may assign the
benefit of the provisions of this Lease and the covenants undertakings and
agreements of the Surety hereunder to any third party and the Surety shall join
in such documents as may be necessary to effect such assignment

1.11   Interest on Late Payment
       ------------------------

       The Surety will pay Interest on all sums payable by it to the Landlord
hereunder

1.12.  Costs and Expenses
       ------------------

       The Surety will indemnify the Landlord against all the Landlord's legal
and other costs losses charges and expenses (on a full indemnity basis) arising
in connection with any modification amendment release and/or enforcement or
attempted enforcement of or preservation of the Landlord's rights under this
Lease
<PAGE>
 
                                     - 40 -

1.13.  Set-off
       -------

       All payments to be made by the Surety hereunder will be made in full
without any deduction for any set-off or counterclaim the Surety may have
against the Landlord

1.14.  Waiver
       ------

       No delay or omission by the Landlord in exercising any right power or
privilege hereunder shall impair such right power of privilege or be construed
as a waiver of such right power or privilege

1.15.  Invalidity
       ----------

       If at any time any one or more provisions of this Schedule is or becomes
invalid illegal or unenforceable in any respect under any law the validity
legality and enforceability of the remaining provisions hereof shall not be in
any way affected or impaired thereby

                              THE FOURTH SCHEDULE
                              -------------------
                                The Regulations
                                ---------------

1.     The Landlord (which term shall in this Fourth Schedule include the
Superior Landlord) or the Landlord's agents or staff shall be at liberty to
refuse to any person access to the Building if they shall think that such
refusal is for the benefit of the tenants or occupants of the Building

2.     Tenants are not entitled to use the lifts for the carriage of articles
likely to cause damage to the lifts or the Building and the Landlord or the
Landlord's agents or staff shall be at liberty to refuse permission to use the
passenger lifts for the carriage of any goods whatsoever if this shall interfere
with the convenience of the other tenants or occupants of the said building or
be likely to cause damage to the passenger lifts or the Building

3.     Tenants are not entitled to place deposit store or abandon any goods
articles or rubbish whatsoever in the common parts of the said building but
shall place all rubbish only in the bin stores or other areas designated for
that purpose by the Landlord from time to time

4.     Tenants shall not misuse the communal toilet facilities and lifts and in
particular shall not empty tea leaves down the sinks or deposit solid or
obnoxious matter in the toilets
<PAGE>
 
                                     - 41 -

5.     Tenants shall not be entitled to erect nameboards or display notices in
the common parts of the Building but each tenant may have one entry only in
respect of the tenancy on the Landlord's nameboard in the entrance hall of the
Building by arrangement with the Landlord's agents The Landlord reserves the
right to vary the position of any entrance hall nameboard and to rearrange the
disposition of the lettering thereon Nameboards or display notices or lettering
on the entrance door or subsidiary entrance door of the Premises must conform to
the standard design for the Building to be notified to the tenant by the
Landlord or the Landlord's agents

6.     Any services rendered to a tenant by staff employed by the Landlord other
than services referred to in the Fourth Schedule of the Superior Lease hereto
are to be deemed special services for which and for the consequences of which
that tenant shall be entirely responsible and tenants shall not be entitled to
any services from such staff which may in any way interfere with the performance
of their duties to the Landlord or the Landlord's agents

7.     Tenants shall not play or permit or suffer the playing of any musical
instrument or the use of any radio television record-player or other similar
device for the reproduction of any music or sound on or in the Premises so as to
be audible outside the Premises

                                    (THE COMMON SEAL of IBM UNITED KINGDOM
                                    (LIMITED was hereunto affixed in the
                                    (presence of:



                              Director   NJH



                              Secretary  [illegible]
<PAGE>
 
                                     - 42 -


                                    Annex A

                                   Site Plan


[This document is a site plan that shows the Chiswick Centre bordered by
Chiswick High Road, Essex Place and Acton Lane. The Site plan also shows the
available parking spaces.]


<PAGE>
 
                                     - 43 -

                                    Annex B

                                   Floor Plan

[This document is a floor plan that shows the office area that is subject to the
Lease.]


