Rule 8.3 - O2 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  (Note 1)           BARCLAYS PLC

Company dealt in                           O2 PLC
Class of relevant security to which the    ORD GBP 0.001
dealings being disclosed relate (Note 2)
Date of dealing                            23 NOVEMBER 2005



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 securities               271,793,374  (3.10%)                    0          (0.00%)
(2) Derivatives (other                0            (0.00%)                    1,396,576  (0.02%)
than options)
(3) Options and agreements            1,000,400    (0.01%)                    2,000,600  (0.02%)
to purchase/sell
Total                                 272,793,774  (3.11%)                    3,397,176  (0.04%)

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

Class of relevant                           Long                                   Short
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                   26,478                                   1.9650
Purchase                   571,354                                  1.9600
Purchase                   2,843,587                                1.9600
Sale                       571,354                                  1.9600
Sale                       1,000,000                                1.9638
Sale                       2,843,587                                1.9600
Sale                       2,843,598                                1.9600
Purchase                   1,040                                    Transfer
Sale                       117                                      1.9601
Sale                       25,000                                   1.9602
Sale                       20,000                                   1.9629
Sale                       12,000                                   1.9629
Sale                       600                                      1.9634
Purchase                   16,576                                   1.9625
Sale                       3,827                                    1.9575


(b)  Derivatives transactions (other than options)

Product name,      Long/short (Note 6)      Number of securities (Note 7)     Price per unit (Note 5)
e.g. CFD
CFD                Long                     16,576                            1.9625


(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 (GBP)
                varying etc.      relates (Note 7)



(ii) Exercising

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



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


Nature of transaction (Note 8)          Details                        Price per unit (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                                           24 NOVEMBER 2005
Contact name                                                 BARCLAYS CORPORATE SECRETARIAT
Telephone number                                             020 7116 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