Euro Medium Term Note Programme

SUPPLEMENT DATED 12 APRIL, 2006 TO THE BASE PROSPECTUS DATED 8 NOVEMBER 2005

CENTRICA plc

(Incorporated in England and Wales with limited liability under registered number 3033654)

U.S. $2,000,000,000

Euro Medium Term Note Programme

This Supplement (the Supplement) to the Base Prospectus (the Base Prospectus) dated 8 November 2005 constitutes a supplementary prospectus for the purposes of Section 87G of the Financial Services and Markets Act 2000 (the FSMA) and is prepared in connection with the Euro Medium Term Note Programme (the Programme) established by Centrica plc (the Issuer). Terms defined in the Base Prospectus have the same meaning when used in this Supplement.

This Supplement is supplemental to, and should be read in conjunction with, the Base Prospectus issued by the Issuer.

The Issuer accepts responsibility for the information contained in this Supplement. To the best of the knowledge of the Issuer (which has taken all reasonable care to ensure that such is the case) the information contained in this Supplement is in accordance with the facts and does not omit anything likely to affect the import of such information.

Annual Financial Statements published 31 March, 2006

On 31 March, 2006 the Issuer published its audited consolidated financial statements for the year ended 31 December 2005, together with the directors’ and auditors’ reports thereon, which appear on pages 23 to 109 of the annual report for the year ended 31 December 2005, and its audited unconsolidated financial statements for the year ended 31 December 2005, together with the directors’ and auditors’ reports thereon, which appear on pages 110 to 118 of the annual report for the year ended 31 December 2005. Copies of all such reports and financial statements have been filed with the Financial Services Authority and, by virtue of this Supplement, are incorporated in, and form part of, the Base Prospectus. Copies of all documents incorporated by reference in the Base Prospectus can be obtained from the registered office of the Issuer and from the specified office of the Paying Agent for the time being in London as described on page 64 of the Base Prospectus.

To the extent that there is any inconsistency between (a) any statement in this Supplement or any statement incorporated by reference into the Base Prospectus by this Supplement and (b) any other statement in or incorporated by reference in the Base Prospectus, the statements in (a) above will prevail.