President Bush’s press secretary was forced to shrug off a suggestion that Mr Prescott had attacked his Administration’s efforts on the Israel-Palestinian peace process as “crap”.

Tony Snow, asked by a journalist about the alleged remark, tried to play down the episode, saying that President Bush had “been called a lot worse and, I suspect, will be”.

Mr Snow told reporters in Washington: “And there will be piquant names, sort of, hurled his way from time to time, but, you know, that’s part of the burden of leadership.”

The Deputy Prime Minister, who was accused of making the remark at a private meeting with Labour MPs this week, did not deny using the word but issued a carefully worded statement saying: “This is an inaccurate report of a private conversation and it is not my view.”

Harry Cohen, the left-wing Labour MP, insisted that he had done so and said that Mr Prescott had backed Britain’s involvement in the invasion of Iraq only in expectation of American leadership in implementing the “road map” for the Middle East peace process.

Mr Cohen said: “He said he only backed the Iraq war for the road map . . . and he was really lamenting the lack of progress on the road map, and he said quite specifically that the Bush Administration was crap in taking the road map forward.” According to the MP, Mr Prescott also called the President “a cowboy in a Stetson hat”.

Others at the meeting on Tuesday, which was for Muslim MPs and Labour parliamentarians representing Muslim communities, said that they had no recollection of such a remark. Mohammad Sarwar, MP for Glasgow Central, told The Times: “I don’t recall it.”

Despite the dispute over what was said, Mr Prescott was applauded by critics of Tony Blair’s closeness to President Bush. Ian Davidson, a Labour MP, said: “John Prescott is to be commended for his excellent political analysis which is accurate, brief and entirely comprehensible.”

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