Rule 8.3 - CAMBRIDGE ANTIBODY TECHNOLOGY GROUP PLC

FORM 8.3

    DEALINGS BY PERSONS WITH INTERESTS IN SECURITIES REPRESENTING 1% OR MORE
              (Rule 8.3 of the City Code on Takeovers and Mergers)


1.   KEY INFORMATION

Name of person dealing        BARCLAYS PLC
(Note 1)
Company dealt in              CAMBRIDGE ANTIBODY TECHNOLOGY GROUP PLC
Class of relevant security    ORD GBP 0.10
to which the dealings being
disclosed relate (Note 2)
Date of dealing               22 MAY 2006

2.   INTERESTS, SHORT POSITIONS AND RIGHTS TO SUBSCRIBE

(a)  Interests and short positions (following dealing) in the class of relevant
security dealt in (Note 3)

                            Long                    Short

                      Number       (%)          Number     (%)

(1) Relevant          973,297      (1.83%)        12,350   (0.02%)
securities
(2) Derivatives        12,350      (0.02%)        34,889   (0.07%)
(other than
options)
(3) Options and             0      (0.00%)             0   (0.00%)
agreements to
purchase/sell
Total                 985,647      (1.85%)        47,239   (0.09%)


(b)  Interests and short positions in relevant securities of the company, other
than the class dealt in (Note 3)

Class of                    Long                     Short
relevant
security:

                  Number              (%)   Number              (%)

(1) Relevant
securities

(2) Derivatives
(other than
options)

(3) Options and
agreements to
purchase/sell

Total


(c)  Rights to subscribe (Note 3)

Class of relevant security:   Details



3.   DEALINGS (Note 4)

(a)  Purchases and sales

Purchase/sale Number of Securities Price per unit
                                   (GBP)
Purchase      119,968              12.9830
Purchase      1,997                12.9713
Purchase      1,000                12.9019
Purchase      1,097                12.9759
Sale          748                  12.9568
Sale          791                  12.9700

  (b)  Derivatives transactions (other than options)


Product    Long/Short    Number of Securities  Price Per
name,      (Note 6)      (Note 7)              Unit (GBP)
e.g. CFD
CFD        Long          748                   12.9568
CFD        Short         119,968               12.9830
CFD        Short         1,000                 12.9019
CFD        Short         1,097                 12.9759
CFD        Long          87,034                12.9830
CFD        Long          42,188                12.9830
CFD        Long          52,504                12.9830
CFD        Long          44,667                12.9830
CFD        Long          75,301                12.9830

(c)  Options transactions in respect of existing securities

(i)  Writing, selling, purchasing or varying

Product name,   Writing,          Number of          Exercise  Type, e.g.      Expiry   Option money
e.g. call       selling,          securities to      price     American,       date     paid/received
option          purchasing,       which the option             European etc.            per unit (Note
                varying etc.      relates (Note 7)                                      5)


(ii) Exercising

Product name, e.g.  Number of           Exercise price per
call option         securities          unit (Note 5)




(d)  Other dealings (including new securities) (Note 4)


Nature of transaction Details           Price per unit
(Note 8)                                (if applicable)
                                        (Note 5)



4.   OTHER INFORMATION

Agreements, arrangements or understandings relating to options or derivatives


Full details of any agreement, arrangement or understanding between the
person disclosing and any other person relating to the voting rights of
any relevant securities under any option referred to on this form or
relating to the voting rights or future acquisition or disposal of any
relevant securities to which any derivative referred to on this form is
referenced.  If none, this should be stated.





Is a Supplemental Form 8 attached? (Note 9)                 NO


Date of disclosure                         23 MAY 2006
Contact name                               BARCLAYS COMPLIANCE
Telephone number                           0207 116 2913
If a connected EFM, name of
offeree/offeror with which connected
If a connected EFM, state nature of
connection (Note 10)


Notes

The Notes on Form 8.3 can be viewed on the Takeover Panel's website at
www.thetakeoverpanel.org.uk