EXHIBIT A
JOINT FILING AGREEMENT
The undersigned agree that this Tenth Amendment dated March 30, 2010, relating to Argyle Security, Inc., shall be filed on behalf of the undersigned.
         
  MEZZANINE MANAGEMENT FUND IV A, L.P.
 
 
  By:   /s/ Dudley R. Cottingham    
    Name:   Dudley R. Cottingham   
    Title:   Authorized Signatory   
 
  MEZZANINE MANAGEMENT FUND IV COINVEST A, L.P.
 
 
  By:   /s/ Dudley R. Cottingham    
    Name:   Dudley R. Cottingham   
    Title:   Authorized Signatory   
 
  MEZZANINE MANAGEMENT LIMITED
 
 
  By:   /s/ Dudley R. Cottingham    
    Name:   Dudley R. Cottingham   
    Title:   Authorized Signatory