Why MPs are fuming at Legg’s cash demand

From the public perspective, the moans emanating from Westminster over Sir Thomas Legg's demand that MPs repay huge chunks of their expenses claims is surely the last straw. They were caught with their trousers down and their hands in the till and now they want our sympathy.

Which is why all three party leaders - Gordon Brown, David Cameron and Nick Clegg - have come out in the past 24 hours saying any MP in their party asked to repay taxpayers' money should do so without hesitation. Cameron has been the most forceful - as he was at the time of Daily Telegraph expenses leak earlier this year - saying today that any Tory MP refusing to pay up will be fired.

And yet, and yet... The fact remains that the MPs have reason to be upset. They believe Legg has rewritten the remit of his inquiry - which was to examine MPs' claims by the "rules and standards in force at the time".

Instead, he has imposed retrospective caps. For instance, he has applied a £1,000 annual limit to gardening expenses and a £2,000 limit on cleaning. Yet there were no such limits in place when MPs made their claims. (It is the Legg limit on cleaning bills which has meant Gordon Brown himself being asked to cough up nearly £12,500.)

According to the BBC's political editor Nick Robinson, who has read Legg's own explanation of his retrospective caps, Sir Thomas found it difficult to interpret "the rules and standards in force at the time" because the Commons Fees Office had allowed so many clearly - as he saw it - disproportionate claims. He felt he had no choice but to introduce reasonable limits.

Which is all very well but, as the Mole wrote when the scandal first broke, while everyone may be agreed that the parliamentary allowances system is absurd and needs overhauling, it was the system in place when these MPs put in for their expenses.

Putting aside those who flagrantly abused the system - especially by flipping their nominations of main and second homes in order to exploit mortgage interest claims - the majority were simply following the House rules.

As one MP explained to the Mole earlier this year, "On day one as a new MP, I was told to go along to the Speaker's Office where expenses would be explained to me. And it was made absolutely plain not only that I was entitled to claim £24,000 a year - but that I should.

"I was told I would be allowed to claim for mortgage interest on a second home, furnishings, maintenance, a certain amount of food bills, whatever. The only advice was: just keep the receipts."

As Tory Ann Widdecombe - one of the many MPs stepping down at the coming general election - told Sky News: "For any employer to say to an employee: 'You stuck to the rules but I have changed them and as a result here's a bill' - that employer would end up in front of a tribunal."

Tricky.