24 June 2009
Completion of Recommended Offer for ATI

Further to the announcement released by ATI on 23 May 2009, the Board of ATI is pleased to announce that the acquisition of the Company by Northern has become effective and trading in the new Northern Shares is expected to begin at 8.00 a.m. on 25 June 2009.

The latest date for despatch of New Northern Share certificates and crediting of CREST accounts under the Scheme will be 8 July 2009. In accordance with the Scheme, a total of 7,418,480 New Northern Shares will be issued to Scheme Shareholders on the register at 6.00 p.m. on 22 June 2009. In addition, pursuant to the proposals made in the Warrantholder Circular dated 28 April 2009, 279,787 New Northern Shares and 408,750 new warrants over shares in the capital of Northern will be issued to former ATI Warrantholders.

ATI will be withdrawn from trading on PLUS at 16.30 p.m. today.

Terms and expressions used in this announcement shall have the same meanings given to them in the announcements released by Northern on 3 April 2009 and 29 April 2009.

For further information contact

ATI Oil Plc
Per Gunnar Løge, Chief Executive
Chris Foss, Finance Director
Tel: 020 7469 2940

KBR (Financial Adviser)
Hugh Oram
Tel: 020 3100 8300

Northern Petroleum Plc
Tel: +44 (0) 20 7469 2900
Richard Latham, Chairman
Graham Heard, Exploration & Technical Director

Investec (NOMAD and Financial Adviser)
Tel: +44 (0) 20 7597 5000
Michael Ansell / Patrick Robb / Avital Lobel