Slaughter and May, Linklaters and Simmons & Simmons have become the latest firms to win roles on the billion-pound bidding battle for Cove Energy.

Slaughters is advising Thailand's PTT Exploration and Production (PTTEP), which has topped an earlier bid from Royal Dutch Shell with a new £1.2bn offer. Cove's directors have unanimously recommended that its shareholders accept the latest bid.

The magic circle firm's team for the state-owned company includes corporate and commercial partners Hywel Davies and David Watkins, who are based in London and Hong Kong respectively, as well as City finance partner Peter Lake.

Linklaters and Simmons, meanwhile, are acting for UBS, the underwriter of PTTEP's takeover proposal. Linklaters is advising UBS on the bank facility and debt bridge arrangements, while Simmons is acting for the bank in relation to its financial adviser role.

City corporate partner Colin Bole is leading the Simmons team, which also includes corporate partner Edward Baker and banking partners John Hayward and Philip Abbott.

Bole commented: "The Cove transaction is a very interesting deal to be working on. It involves one of the furthest progressed formal sale processes under the new rules of the UK Takeover Code which came into effect in September 2011."

As previously reported by Legal Week, Cove, which is based in London and holds oil and gas assets in Kenya, Mozambique and Tanzania, is being advised by LG, with corporate partners Geoff Gouriet and John Reed leading the firm's team.

Shell is being advised by Clifford Chance, with London corporate partner Tim Lewis leading the magic circle firm's team, while Herbert Smith is advising Shell financial adviser Morgan Stanley with a team led by corporate partner Malcolm Lombers.

PTTEP's bidding war with Shell dates back to February, after Cove announced a formal sale process for the company under the Takeover Code on 5 January.