Centrica PLC — Audit Report / Information 2012

Mar 27, 2013

SUPPLEMENT DATED 27 MARCH, 2013 TO THE BASE PROSPECTUS DATED 26 SEPTEMBER, 2012

CENTRICA plc

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

U.S.\$8,000,000,000 Euro Medium Term Note Programme

This Supplement (the Supplement) to the Base Prospectus dated 26 September, 2012 (the Base Prospectus), which comprises a base prospectus, 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 and any other supplements to 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.

Purpose of the Supplement

The purpose of this Supplement is (a) to incorporate by reference the auditor's report and audited consolidated and non-consolidated annual financial statements of the Issuer for the financial year ended 31 December, 2012 and (b) to update the "Significant or Material Change" statement set out in the Base Prospectus.

Annual Report and Accounts for the period ended 31 December, 2012

On 27 March, 2013, the Issuer published its annual report and accounts for the period ended 31 December, 2012 (the Annual Report).

A copy of the Annual Report has been filed with the Financial Services Authority and, by virtue of this Supplement, the auditor's report and audited consolidated and non-consolidated annual financial statements for the financial year ended 31 December, 2012, which appear on pages 76 to 144 of the Annual Report, are incorporated in, and form part of, the Base Prospectus.

The credit ratings of the Group referred to on page 96 of the Annual Report have been assigned by Moody's Investors Service Ltd (Moody's) and Standard & Poor's Credit Market Services Europe Limited (S&P). Each of Moody's and S&P is established in the European Union and is registered under Regulation (EC) No. 1060/2009. As such, Moody's and S&P are included in the list of credit rating agencies published by the European Securities and Markets Authority on its website in accordance with such Regulation.

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.

Copies of all documents incorporated by reference in the Base Prospectus are also available on the National Storage Mechanism,

If documents which are incorporated by reference themselves incorporate any information or other documents therein, either expressly or implicitly, such information or other documents will not form part of this Supplement for the purposes of the Prospectus Directive (Directive 2003/71/EC) except where such information or other documents are specifically incorporated by reference or attached to this Supplement.

Any non-incorporated parts of a document referred to in this Supplement are either deemed not relevant for an investor or are otherwise covered elsewhere in this Supplement or the Base Prospectus.

General Information

There has been no significant change in the financial or trading position of the Issuer and its Subsidiaries taken as a whole since 31 December, 2012 and there has been no material adverse change in the financial position or prospects of the Issuer and its Subsidiaries taken as a whole since 31 December, 2012.

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.

Save as disclosed in this Supplement and any supplement to the Base Prospectus previously issued, there has been no other significant new factor, material mistake or inaccuracy relating to information included in the Base Prospectus since the publication of the Base Prospectus.