CMS Cameron McKenna has won a trophy role on BP's $7bn (£4.7bn) asset sale, joining Sullivan & Cromwell and a host of international law firms, writes The American Lawyer.

The sale to Houston-based Apache – which involved oil and gas assets in Canada, Egypt and the US – is part of a bid by BP to shore up its balance sheet and cope with mounting costs stemming from the controversial oil leak in the Gulf of Mexico.

Sullivan & Cromwell served as global coordinating counsel to BP on the deal. James Morphy, the former head of the firm's M&A practice, advised BP along with M&A partner and IP co-head John Evangelakos and finance partner Christine Spillane.

The New York leader has a long relationship with the company. The firm advised BP when it acquired California-based oil company ARCO for $27bn (£18bn) in 1999. Sullivan antitrust partner Juan Rodriguez previously served as European antitrust counsel in BP's central in-house legal department in London.

Camerons is acting as UK counsel to BP, fielding a team led by oil and gas group head Penelope Warne including energy partners Eleanor Layton and Stephen Millar.

Also advising BP were Texan firm Gardere Wynne Sewell and Canadian law firm Fraser Milner Casgrain. Jens Bertelsen, an associate general counsel in BP's M&A group in London, led an in-house legal team working on the deal.

Under the terms of the agreement with Apache, BP will sell the company's oil and gas assets in the Permian basin in Texas and New Mexico, upstream natural gas reserves in Alberta and British Colombia, and business and exploration concessions in Egypt's Western Desert.

Slaughters acted as UK counsel to Apache, fielding a team under M&A partner Charles Randell and antitrust chair Philippe Chappatte. Apache's legal team was led by general counsel Anthony Lannie.

Apache was advised by US firm Bracewell & Giuliani, which fielded a 27-lawyer team led by chairman and energy partner Patrick Oxford, while Osler Hoskin & Harcourt in Calgary handled Canadian law issues for the acquirer.

The deal comes after news emerged this month that BP has instructed Freshfields Bruckhaus Deringer to advise on takeover defence work amid fears that the oil giant could become a target in the wake of the oil spill, which has severely hit the company's share price.

BP has already spent more than $3.12bn (£2bn) cleaning up the spill, which began in April, with the company's liabilities expected to rise dramatically.

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