December 16 2009 SECURITIES EXCHANGE COMMISSION 450 Fifth Street NW Washington DC 20549 Attn. Document Control RE	American Depositary Shares evidenced by One 1 American Depositary Receipts representing OneFifth of One 15 Share of Cairn Energy PLC Form F6 File No 333154286 Ladies and Gentlemen Pursuant to Rule 424b3 under the Securities Act of 1933 as amended on behalf of The Bank of New York Mellon as Depositary for securities against which American Depositary Receipts are to be issued we attach a copy of the new prospectus Prospectus reflecting the change in number of ordinary shares represented by one American Depositary Share the Ratio. As required by Rule 424e the upper right hand corner of the Prospectus cover page has a reference to Rule 424b3 and to the file number of the registration statement to which the Prospectus relates. Pursuant to Section III B of the General Instructions to the Form F6 Registration Statement the Prospectus consists of the ADR certificate with revised ratio for Cairn Energy PLC. The Prospectus has been revised to reflect the new ratio and has been overstamped with EFFECTIVE 22 2009 THE AMERICAN DEPOSITARY SHARE ADS RATIO WILL CHANGE FROM 115 ONE ADS REPRESENTING ONE FIFTH OF AN ORDINARY SHARE TO 12 ONE ADS REPRESENTING TWO ORDINARY SHARES WITH A NEW PAR VALUE OF 0.61538 PENCE EACH SHARE. Please contact me with any questions or comments at 212 8154888 Vanessa Salazar Vice President The Bank of New York Mellon ADR Division Encl. CC Paul Dudek Esq. Office of International Corporate Finance Depositary Receipts 101 Barclay Street 22nd Floor West, New York, NY 10286