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               18 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)





(1) Relevant            865,194    (1.63%)     147,022     (0.28%)
securities
(2) Derivatives         147,022    (0.28%)     377,626     (0.71%)
(other than
options)
(3) Options and               0    (0.00%)           0     (0.00%)
agreements to
purchase/sell
Total                 1,012,216    (1.90%)     524,648     (0.99%)


(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      4,836                12.9865
Purchase      19,000               12.9785
Purchase      59,949               12.9980

(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        Short         19,000                12.9785
CFD        Short         4,836                 12.9865
CFD        Short         59,949                12.9980
CFD        Long          563                   12.98
CFD        Long          3,480                 12.98
CFD        Long          43,132                12.9980
CFD        Long          273                   12.98
CFD        Long          1,686                 12.98
CFD        Long          20,902                12.9980
CFD        Long          341                   12.98
CFD        Long          2,098                 12.98
CFD        Long          26,017                12.9980
CFD        Long          293                   12.98
CFD        Long          1,065                 12.98
CFD        Long          22,318                12.9980
CFD        Long          499                   12.98
CFD        Long          1,799                 12.98
CFD        Long          37,631                12.9980


(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                         19 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