Brown's staying power called into question

Gordon Brown may not lead the Labour party into the next general election, former welfare minister Frank Field has said.

Mr Field, leader of the backbench rebellion over the 10p tax band fiasco, made the suggestion as he launched a devastating attack on his party leader.

He also said the prime minister experienced "indescribable rages" and was "unhappy inside his own body".

"That's clearly part of the tragedy - on a personal level as well for a party, government and country level - that somebody whose real aim in life is to be prime minister, now has the task and seems so lacking in enjoyment in trying to carry it out," he said.

The interview, on the BBC's World Service, reflects a new level of confidence among disgruntled Labour MPs following the party's massacre at the recent local elections.

The ex-minister claimed anger over the 10p tax rate was of a level he had not seen before and hinted it could see the Budget being voted down.

The comments risk drawing attention away from Mr Brown's attempt to regain the initiative this morning with a speech on social care.

They also come hot on the heels of damaging memoir revelations from Lord Levy, Cherie Blair and former deputy prime minister John Prescott.

Mr Field, speaking on Any Questions? on Friday, said: "I do believe the stakes are very, very high for the prime minister indeed – if his backbenchers are not satisfied by...the form that the compensation package will take, it may destroy his premiership."

The prime minister has refused to respond to the accusation. At a press briefing this morning a spokesman said: "The prime minister's view is that he's not going to be distracted and what he's focusing on are the big issues facing the country."