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                            22 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               275,654,422   (3.14%)                    0          (0.00%)
(2) Derivatives (other                0             (0.00%)                    1,413,152  (0.02%)
than options)
(3) Options and                       1,000,400     (0.01%)                    2,000,600  (0.02%)
agreements to
purchase/sell
Total                                 276,654,822   (3.16%)                    3,413,752  (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                   38,929                                   1.9625
Purchase                   4,267                                    1.9650
Purchase                   8,036                                    1.9650
Purchase                   6,377                                    1.9650
Purchase                   3,796                                    1.9650
Purchase                   8,036                                    1.9650
Purchase                   4,267                                    1.9650
Purchase                   4,062                                    1.9650
Purchase                   4,062                                    1.9650
Purchase                   5,425                                    1.9650
Purchase                   5,425                                    1.9650
Purchase                   14,428                                   1.9650
Purchase                   3,796                                    1.9650
Purchase                   4,799                                    1.9650
Purchase                   6,377                                    1.9650
Purchase                   3,425                                    1.9650
Purchase                   3,425                                    1.9650
Purchase                   14,428                                   1.9650
Purchase                   4,799                                    1.9650
Sale                       2,832                                    1.9600
Sale                       500,000                                  1.9600
Sale                       4,000                                    1.9602
Sale                       5,000                                    1.9601
Sale                       6,500                                    1.9602
Sale                       11,500                                   1.9602
Sale                       1,690                                    1.9601
Sale                       6,000                                    1.9601
Sale                       9,000                                    1.9601
Sale                       1,000                                    1.9601
Sale                       3,000                                    1.9602
Sale                       2,600                                    1.9601
Sale                       4,000                                    1.9601
Sale                       12,300                                   1.9601
Sale                       1,950                                    1.9601
Sale                       676                                      1.9601
Sale                       780                                      1.9601
Sale                       7,500                                    1.9602
Sale                       1,500                                    1.9602
Sale                       3,000                                    1.9602
Sale                       12,000                                   1.9601
Sale                       3,500                                    1.9601
Sale                       156                                      1.9601




 (b)  Derivatives transactions (other than options)

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



 (c)  Options transactions in respect of existing securities

 (i)  Writing, selling, purchasing or varying

 (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 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