While several have been open about their individual circumstances, some have not wanted to disclose details until the three-week process is over. Others have refused to comment or failed to respond to enquiries.

A number of Scots have been told they need repay nothing. Others, mainly for reasons of administrative errors, have been asked to pay back money for overpayment of cleaning or utility bills, rent or mortgage payments.

Thus far, Gordon Brown has written out the largest cheque – for £12,415, mainly for cleaning services.

Some of his Scottish colleagues are querying Sir Thomas’s requests for repayment, pointing out that the administrative mistakes were not theirs but those of the Commons Fees Office.

“It’s a total shambles. The Fees Office needs a complete overhaul. They’ve messed things up big time,” declared one disgruntled MP.

After initially focusing on cleaning and gardening expenses, it seems clear Sir Thomas is now also looking at rent and mortgage payments. This is particularly worrying MPs as the payback requests could run into many thousands of pounds.

Labour’s Jim McGovern, the Dundee MP, has been asked to repay £5200 in mortgage payments, a request he is appealing against because he is adamant that error is not down to him but to the Fees Office.

Anger has also been directed at the Prime Minister, with one Labour back bencher saying many of her colleagues felt “bitterly let down” by his failure to defend them.

Claire Curtis-Thomas, who represents Crosby on Merseyside, said Labour MPs were “pretty damning” about

their leader’s response to the audit and suggested Mr Brown might have been “cowed” by having overcharged the taxpayer by more than £12,000.

Her comments came as David Wilshire, the Conservative back bencher, reported himself to John Lyon, the parliamentary standards commissioner, over allegations he used Commons expenses to pay more than £100,000 of public money into his own company.

The Surrey MP claimed he had abided by the rules but last night, after being hauled before Patrick McLoughlin, the party Chief Whip, to explain himself, issued a statement, saying he would stand down at the General Election.

“I have reluctantly concluded it is sensible for me not to seek re-election next year,” said Mr Wilshire.

Meantime, John Bercow, the Commons Speaker, and Boris Johnson, the London Mayor, became the latest politicians to repay expenses.

Mr Bercow paid back an “accidental overclaim” of £978 for mortgage interest, while Mr Johnson returned £1266 he claimed for council tax while an MP.

In a separate development, Harriet Harman appeared to take a different tack to Sir Thomas’s audit from the PM.

While Mr Brown has effectively told his colleagues to shut up and pay up, the Commons Leader suggested to MPs that if they felt hard done by they should challenge the ex-civil servant’s ruling.

In a thinly-veiled shot across Sir Thomas’s bows, Ms Harman said: “Obviously, we have to judge things by the rules and standards that obtained at the time. To do anything else would be arbitrary.”

The former mandarin has incensed many MPs by imposing a backdated cap of £2000 a year for cleaning and £1000 for gardening at their second homes.

However, Mr Bercow backed his approach, saying he believed limits were “implicit” at the time of the claims.

Suggesting the financial pain being suffered by some MPs was a price worth paying to show voters they were serious about cleaning up Westminster, the Speaker says in a BBC interview to be broadcast tomorrow:

“If there is a choice of headlines between ‘payback time’ on the one hand and ‘Westminster whitewash’ on the other, I would much rather have the former than the latter.”

Analysis

Seething anger does not tell the half of it. MPs are fuming at what they see as the gross injustice of “Witchfinder General” Sir Thomas Legg, the ex-Whitehall mandarin who is poring over their expense claims and asking them to write out cheques for thousands of pounds.

Much of the honourable members’ ire is directed at the Commons Fees Office, which, they claim, has been responsible not only for promoting a flawed expenses system but also for a series of administrative cock-ups – wrong payments, documents going missing, etcetera.

Unremarkably, those MPs who have been given the all-clear, so to speak, have been publishing their Legg letters with alacrity.

The others tell you where to get off, politely or otherwise, or explain their positions involving requests for repayments, clarifications, etcetera, or will not comment until the process ends.

Yesterday, Harriet Harman veered off message and told her parliamentary colleagues if they had a problem with Sir Thomas’s findings, they should challenge them.

In a clear shot across his bows, the Commons Leader told MPs: “Obviously, we have to judge things by the rules and standards that obtained at the time. To do anything else would be arbitrary.”

So Sir Thomas’s retrospective limits on MPs’ cleaning and gardening bills are unjust?

The content and tone of Ms Harman’s message were at odds with Gordon Brown’s hardline stance that MPs should shut up and pay up.

The PM, like Messrs Cameron and Clegg, is ­desperate to draw a line under this whole affair and avoid it dominating the election campaign.

Yesterday he said: “Our duty is to clean up politics.

If people think we are going slow or going to be hesitant in the cleaning up of politics, they will draw their own conclusions.”

Asked about the apparent difference between the PM and Ms Harman, No 10 said they both backed Sir Thomas’s terms of reference and believed the review was ­­important to restore public confidence.

The unhappiness some Labour MPs have with their leader was expressed by backbencher Clare Curtis-Thomas, who complained he had “bitterly let down” his colleagues, appearing to have been “cowed” after having to repay more than £12,000, which was mainly for cleaning costs.

Yet for all MPs’ fury, the voters will remain ­unimpressed because, on the issue of expenses, they regard the political class as guilty.

Any parliamentary ­whining will simply make matters worse.

Sir Thomas Legg