Gordon Brown's problems over the expenses paid to MPs mounted last night when he came under all-party pressure to scrap tomorrow's Commons vote on reforming the system.
And Charles Clarke, the former Home Secretary, agreed that tomorrow's debate should be scrapped after Mr Brown was forced to abandon his plan to replace the MPs' 24,000-a-year "second homes" allowance with a daily payment for attending the Commons worth about £150 a day.
The Commons Standards and Privileges Committee urged MPs to defy the Prime Minister by delaying changes to their expenses until after an independent inquiry into the system reports later this year.
Committee members, who have tabled motions calling for a decision to be postponed, believe that only independent proposals will command public support and the Commons should not "pre-empt" the review already under way by the separate Committee on Standards in Public Life.
Mr Clarke said the Prime Minister should not "bully" MPs into changing the expenses system, adding that he had been "damaged" by his ill-fated attempt to secure reform by "diktat".
He was the second Blairite former Cabinet minister to attack Mr Brown this week, after Stephen Byers, the former Transport Secretary, criticised the announcement of a 50p rate of income tax for high earners in last week's Budget. Labour MPs believe the Prime Minister's authority has been dented.
Brown aides insisted the vote on other aspects of the expenses regime would go ahead,. Reforms include requiring MPs to submit receipts for all claims, full disclosure of their outside earnings and for their staff to be employed centrally by the Commons.
Last night ministers challenged David Cameron to back these reforms tomorrow rather than support a delay. "This is a key test for him: is he going to vote for changes he supports or be an opportunist?" one said.
Mr Brown, speaking during a visit to Poland, dismissed as "ridiculous" the idea he had been forced into a climbdown, saying that "major progress" had been made on the reforms.
In another setback for Mr Brown, the Committee on Standards in Public Life dashed Mr Brown's hopes that it would look separately at the "second homes" allowance and would complete its work by July. Labour MPs joined criticism by opposition parties of the Prime Minister's handling of the issue. Sir Stuart Bell, a senior Labour MP, said the mood at Monday's meeting of the Parliamentary Labour Party was "very sour", adding: "The blame for this was laid at officials at Downing Street. He was badly advised."
Last night, Shadow Commons leader Alan Duncan said: "In a desperate panic he's gone from YouTube through a U-turn and down the tube itself. It's a shambles and a farce."