Debevoise & Plimpton has made up four lawyers to its partnership, including one in the US firm's City base.

Litigator Sophie Lamb (pictured) will join the firm's partnership in London as of 1 July. Her practice focuses on complex litigation, commercial and investment treaty arbitration and public international law.

Lamb joined Debevoise as an international counsel in 2008 from Bird & Bird, where she was a partner.

She becomes the 20th partner in the firm's City office, which is headed up by James Scoville. A number of the partners based in London divide their time between the firm's international offices.

The New York-based firm did not make up any new partners in London in 2009, when two were promoted in Moscow and New York. The last lawyer to join the partnership in the City was litigator Karolos Seeger in 2008.

The three other promotions in this year's round come in Debevoise's New York headquarters, with corporate lawyers Paul Rodel and Jeffrey Ross made up alongside litigator Helen Cantwell.

The partners promotions season has been in full swing at UK firms in recent weeks with Clifford Chance on Tuesday (4 May) promoting 22 partners around the world, including five in the City.