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 BARCLAYS PLC (Note 1) Company dealt in O2 PLC Class of relevant security ORD GBP 0.001 to which the dealings being disclosed relate (Note 2) Date of dealing 16 DECEMBER 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 270,769,588 (3.09%) 122,977 (0.00%) securities (2) Derivatives 0 (0.00%) 325,000 (0.00%) (other than options) (3) Options and 1,001,400 (0.01%) 2,000,600 (0.02%) agreements to purchase/sell Total 271,770,988 (3.10%) 2,448,577 (0.03%) (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 151,398 1.9700 Purchase 123,564 1.9653 Purchase 5,445 1.9600 Purchase 555 Transfer Purchase 303,174 1.9700 Purchase 17,306 1.9650 Sale 15,114 1.9654 Sale 45,736 1.9650 Sale 67,572 1.9650 Sale 151,398 1.9700 Sale 1,201 1.9676 Sale 222 1.9676 Sale 597 1.9676 Sale 88 1.9676 Sale 460 1.9651 Sale 822 1.9651 Sale 1,000 1.9676 Sale 72 1.9676 Sale 608 1.9651 Sale 88 1.9676 (b) Derivatives transactions (other than options) Product Long/Short Number of Securities Price Per name, (Note 6) (Note 7) Unit (GBP) e.g. CFD (c) Options transactions in respect of existing securities (i) Writing, selling, purchasing or varying Product Writing, Number of Exercise Type,e.g. Expiry Option money name, selling, securities price American, date paid/received e.g. call purchasing to which European per unit (note 5) option , varying the option etc. etc. relates (Note 7) (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 DECEMBER 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

Companies

Barclays (BARC)
UK 100