Blocklisting Interim Review

Cambridge Antibody Tech Group PLC
13 April 2006

                        BLOCK LISTING SIX MONTHLY RETURN



Information provided on this form must be typed or printed electronically.



To:  The FSA



Date: 13 April 2006


AVS No: 


Name of applicant:                                        Cambridge Antibody Technology Group plc

Name of scheme:                                           Share Incentive Plan (formerly All Employee Share Ownership
                                                          Plan)

Period of return:                          From:          1 October 2005  To: 31 March 2006

Balance under scheme from previous return:                181,902

The amount by which the block scheme has been increased,  100,000
if the scheme has been increased since the date of the
last return:

Number of securities issued/allotted under scheme during  115,095
period:

Balance under scheme not yet issued/allotted at end of    166,807
period

Number and class of securities originally listed and the  22,136,251 ordinary 10 pence shares
date of admission                                         25 March 1997

Total number of securities in issue at the end of the     53,100,133
period


Name of contact:                                           Justin Hoskins

Address of contact:                                        Milstein Building, Granta Park, Cambridge CB1 6GH

Telephone number of contact:                               01223 471 471



SIGNED BY   Justin Hoskins, Company Secretary

Director/company secretary/suitably experienced employee/duly authorised
officer,

for and on behalf of



Cambridge Antibody Technology Group plc

Name of applicant



If you knowingly or recklessly give false or misleading information you may be
liable to prosecution.


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