BP has sought to play down a new row in the United States by insisting that a decision to freeze nearly £2 million in pay owing to Lord Browne of Madingley, its former chief executive, and John Manzoni, its former head of refining and marketing, was taken with their support.

A spokesman for the oil group said yesterday that the move to withhold payment, as demanded by lawyers acting for rebel shareholders seeking damages from BP, was “voluntary”.

He said: “The decision to withhold the payments was taken with the full backing of John Browne and John Manzoni. We want to progress the case.”

Mary Blasy, a lawyer for Lerach Coughlin, which is representing the investor group, claimed a significant victory. She insisted that if the payments had not been frozen, both former directors could have escaped any penalty, given that they had already left their jobs.

“We’re maintaining the financial status quo until we reach the end of the case,” Ms Blasey said. “With both men leaving the company, we were afraid we’d end up with them being released from liability. Now that won’t happen.”

The rebel investor group filed a 100-page lawsuit in Alaska last October, seeking unspecified compensation for the damage done to the BP share price by the Texas City refinery blast and pipeline leaks in Alaska. At the time, BP’s shares had fallen 20 per cent below their high of 2006, wiping £30 billion from the value of the group.

William Lerach, a class-action lawyer, said that the lawsuit would send a clear message to BP to improve its North American operations.

Both Lord Browne and Mr Manzoni are entitled to a year’s pay under the terms of their departures from BP. Lord Browne, who resigned in May after being found to have lied in the High Court, is due to receive more than £1.5 million. He has already missed out on a £15.5 million bonus and share award package as a result of his resignation.

Legal experts said that the request from Lerach Coughlin was probably intended to put more pressure on BP and bring it to the negotiating table. One said: “It seems strange that they’re worried about these two directors leaving the company when others among the 39 managers and directors named in the lawsuit have also left.”

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