GORDON Brown's authority was crumbling tonight after he scrapped a vote to axe MPs' notorious second-home expenses to avoid a second humiliating defeat in just 24 hours.

The prime minister pulled back from a showdown on linking claims to "attendance at Westminster" when it became obvious that the measure would fail to win backing on the Commons floor.

A second reverse - the day after the embarrassment of defeat over his "shameful" treatment of former Gurkhas - would have been disastrous for Mr Brown's credibility.

Even so, MPs were openly comparing his leadership to the dying days of John Major's government after a fortnight of terrible headlines triggered by the Damian McBride "sleazegate" affair.

Labour backbenchers are furious at No.10's failure to see disaster looming, whether it involves the right of Gurkhas to stay in Britain or the cackhanded attempts to reform Westminster expenses.

Tom Harris, a former minister, said: "Governments fall apart when discipline fails. Major's government collapsed when his MPs saw no reason to toe the party line."

And Barry Sheerman, the Labour chairman of the Children's select committee, said: "MPs on all sides, but particularly the Labour side, are angry and frustrated at the way in which these changes were bounced on us without consultation."

For the first time since Mr Brown's recovery after the banking collapse last September, some MPs are questioning whether he can survive in office through to a General Election next year.

Further big hurdles lie ahead, including likely heavy losses in the local and European elections on June 4 - and the publication of 1.2m MPs' expenses' receipts in July.

The latest climbdown came when the government accepted an amendment to leave the toxic issue of second-home allowances to the independent 'anti-sleaze' committee, under Sir Christopher Kelly.

Just two days before raising the white flag, Mr Brown's aides were branding any MPs backing further delay on the controversy as "the forces of reaction".

To add to his embarrassment, the prime minister personally launched his bid to scrap the 24,000 annual second-home claims in a much-lampooned video on YouTube.

In the chamber, some MPs were shouting "car crash". Tory frontbencher Alan Duncan called it "complete and utter lunacy", while Liberal Democrat David Heath preferred "farce".

Trouble loomed once Tory leader David Cameron announced he would not support the linking of allowances to "attendance at Westminster" because it revived the idea of a "daily rate" - dropped by Mr Brown on Monday.

The Conservative leadership also abstained on a motion forcing MPs to declare full details of all outside jobs because, Mr Cameron said, it went too far, even requiring the declaration of "a basket of strawberries".

However that measure did pass, forcing MPs with lucrative outside earnings - including Alan Milburn (Darlington) and William Hague (Richmond) - to declare exactly how much they are paid and what hours they work.

Thirty one MPs voted to keep full details of outside jobs under wraps, including David Curry, Tory MP for Skipton and Ripon, and former Conservative leader Michael Howard.

The other proposals approved will stop MPs living within 20 miles of London qualifying for any second-home allowance, require receipts to back up all claims and require MPs' staff to be employed centrally.

It was clear that Downing Street's strategy was an attempt to save face, by allowing Mr Brown to claim that at least some of his proposals had got through.

The prime minister's spokesman dismissed suggestions that he had climbed down over reforms and was losing authority as "complete rubbish".

But a claim by Liam Byrne, the Cabinet Office minister, that Mr Brown had displayed "the smack of firm government" on the expenses issue was not widely shared at Westminster.