<DOCUMENT>
<TYPE>EX-99.L
<SEQUENCE>8
<FILENAME>a2095632zex-99_l.txt
<DESCRIPTION>EXHIBIT 99.L
<TEXT>

<Page>


                    SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP
                                FOUR TIMES SQUARE
                             NEW YORK, NY 10036-6522

                                 (212) 735-3000

                                December 6, 2002


BlackRock Insured
Municipal Income Trust
40 East 52nd Street
New York, New York 10022

                           Re:      BlackRock Insured Municipal Income Trust
                                    REGISTRATION STATEMENT ON FORM N-2

Ladies and Gentlemen:

     We have acted as special counsel to BlackRock Insured Municipal Income
Trust, a statutory trust (the "Trust") created under the Delaware Statutory
Trust Act (the "Delaware Statutory Trust Act"), in connection with the public
offering by the Trust of up to 3,053 shares of the Trust's Series T7 Preferred
Shares of Beneficial Interest, 3,053 shares of the Trust's Series R7 Preferred
Shares of Beneficial Interest and 3,053 shares of the Trust's Series F7
Preferred Shares of Beneficial Interest, in each case having liquidation
preference $25,000 per share (individually, "Series of Preferred Shares" and
together, the "Preferred Shares").

     This opinion is being furnished in accordance with the requirements of Item
24 of the Form N-2 Registration Statement under the Securities Act of 1933, as
amended (the "1933 Act"), and the Investment Company Act of 1940, as amended
(the "1940 Act").


     In connection with this opinion, we have examined originals or copies,
certified or otherwise identified to our satisfaction, of (i) the Notification
of


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BlackRock Insured
Municipal Income Trust
December 6, 2002
Page 2

Registration of the Trust as an investment company under the 1940 Act, on
Form N-8A, dated August 19, 2002 as filed with the Securities and Exchange
Commission (the "Commission") on August 19, 2002, (ii) the Registration
Statement of the Trust on Form N-2 (File Nos. 333-100951 and 811-21178), as
filed with the Commission on November 1, 2002 under the 1933 Act and the 1940
Act, Pre-Effective Amendment No. 1 thereto, as filed with the Commission on
December 5, 2002, and Pre-Effective Amendment No. 2 to be filed with the
Commission on the date hereof, under the 1933 Act (such Registration
Statement, as so amended and proposed to be amended, being hereinafter
referred to as the "Registration Statement"); (iii) the form of the
Underwriting Agreement (the "Underwriting Agreement") proposed to be entered
into between the Trust, as issuer, BlackRock Advisors, Inc., as investment
adviser to the Trust, BlackRock Financial Management, Inc., as investment
sub-adviser to the Trust, and Salomon Smith Barney Inc. and Merrill Lynch,
Pierce, Fenner & Smith Incorporated, as representatives of the several
underwriters named therein (the "Underwriters"), filed as an exhibit to the
Registration Statement; (iv) a specimen certificate representing each Series
of Preferred Shares; (v) the Corrected Certificate of Trust, as filed with
the Secretary of State of Delaware, and the Amended and Restated Agreement
and Declaration of Trust of the Trust, as currently in effect; (vi) the
Statement of Preferences setting forth the rights, powers, terms and
preferences of each Series of Preferred Shares; (vii) the Amended and
Restated By-Laws of the Trust, as currently in effect; (viii) certain
resolutions of the Board of Trustees of the Trust relating to the creation,
issuance and sale of the Preferred Shares and related matters and (ix)
certain resolutions of the shareholders of the Trust relating to the creation
of each Series of Preferred Shares. We also have examined originals or
copies, certified or otherwise identified to our satisfaction, of such
records of the Trust and such agreements, certificates of public officials,
certificates of officers or other representatives of the Trust and others,
and such other documents, certificates and records as we have deemed
necessary or appropriate as a basis for the opinions set forth herein.

     In our examination, we have assumed the legal capacity of all natural
persons, the genuineness of all signatures, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents submitted to us as certified, conformed or photostatic copies and
the authenticity of the originals of such copies. In making our examination
of documents, we have assumed that the parties thereto, other than the Trust,
had or will have the power, corporate or other, to enter into and perform all
obligations

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BlackRock Insured
Municipal Income Trust
December 6, 2002
Page 3


thereunder and have also assumed the due authorization by all requisite
action, corporate or other, and execution and delivery by such parties of
such documents and the validity and binding effect thereof on such parties.
In rendering the opinion set forth below, we have assumed that the share
certificates representing each Series of Preferred Shares will conform to the
specimen examined by us and will have been manually signed by an authorized
officer of the transfer agent and registrar for the Preferred Shares and
registered by such transfer agent and registrar. We have also assumed that
the Underwriting Agreement will be executed in substantially the form
reviewed by us. As to any facts material to the opinions expressed herein
which we have not independently established or verified, we have relied upon
statements and representations of officers and other representatives of the
Trust and others.

     Members of our firm are admitted to the bar in the State of Delaware and we
do not express any opinion as to the laws of any jurisdiction other than the
Delaware Statutory Trust Act.

     Based upon and subject to the foregoing, we are of the opinion that when
(i) the Registration Statement becomes effective; (ii) the Underwriting
Agreement has been duly executed and delivered; (iii) certificates
representing the Preferred Shares in the form of the specimen certificate
examined by us have been manually signed by an authorized officer of the
transfer agent and registrar for the Preferred Shares and registered by such
transfer agent and registrar; and (iv) the Preferred Shares have been
delivered to and paid for by the Underwriters at a price per share not less
than the per share par value of the Preferred Shares as contemplated by the
Underwriting Agreement, the issuance and sale of the Preferred Shares will
have been duly authorized and the Preferred Shares will be validly issued,
fully paid and nonassessable (except as provided in the last sentence of
Section 3.8 of the Agreement and Declaration of Trust)

     We hereby consent to the filing of this opinion with the Commission as an
exhibit to the Registration Statement. We also consent to the reference to our
firm under the caption "Legal Opinions" in the Registration Statement. In giving
this consent, we do not thereby admit that we are included in the category of
persons whose consent is required under Section 7 of the 1933 Act or the rules
and regulations of the Commission.

                                    Very truly yours,


                                    /s/ Skadden, Arps, Slate, Meagher & Flom LLP


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