Juggling too much? Former chairman of the Committee on Standards in Public Life said Gordon Brown failed the acid test when ministers defied him over expenses

Gordon Brown failed the 'acid test' of his leadership when his MPs defied public anger on sleaze, the former standards watchdog said last night.

He was left looking weakened by a Labour stampede to save the lavish expense allowances enjoyed by MPs.

MPs used Mr Brown's absence from the Commons to embarrass their leader over the second homes allowance

Five Cabinet ministers were among 33 ministers who defied his appeals for restraint while both David Cameron and sleaze watchdog Sir Alistair Graham questioned if Mr Brown was serious about change.

Calls were growing for an inquiry into MPs' expenses by the Committee on Standards in Public Life. Last night Downing Street tried to ease the damage by saying it would welcome an inquiry.

Mr Brown will call for more suggestions on bringing greater transparency to the expenses regime which has been hit by scandals involving mainly Tory MPs.

He said he was disappointed by the result of a vote that looked like a deliberate act of rebellion against his authority by Labour MPs.

'I was not happy about what happened,' he added. 'I was disappointed. We voted to keep MPs' pay down and now we must look at the issue of expenses and accountability again.'

But his aides struggled to explain what looked like a political blunder that left 146 Labour MPs free to vote against a package of reforms.

Mr Cameron, by contrast, ordered his Shadow Cabinet to vote for the changes and made clear other Tory MPs should follow their lead. In the end, only 21 Tories voted with Labour against the change.

Home Secretary Jacqui Smith and rising star Andy Burnham were among those who voted against the reform, along with key Brown allies led by his two parliamentary aides Ian Austin and Angela Smith, and deputy chief whip Nick Brown.

'MPs got bogged down in the detail and didn't spot the bigger picture. As a result where we are left is not sustainable,' one aide said.

The result was condemned as ' disappointing' by the former chairman of the Committee on Standards in Public Life, Sir Alistair Graham. He said MPs had 'shot themselves in the foot in a big way'.

He called on MPs to hand the job of reforming the system to the CPSL. 'They would have had to think twice about rejecting advice from a senior, independent outside body.

'This is not going to go away. It should be looked at. We know there is strong public reaction against things like the John Lewis list,' he told the Mail.

Sir Alistair added: 'I hope somebody like the CPSL will go ahead with a further review to try and come up with solutions which have public confidence.

'It doesn't do anything to enhance the credibility of the Government because Gordon Brown made standards a central issue of his campaign for the Labour leadership.

'When it comes to the acid test, he hasn't delivered his own government and I wonder if he is really serious about it.'

Sir Christopher Kelly, the current chairman of the CPSL, said: 'I would expect the public to react very badly.'