MPs were today returning to the House of Commons facing demands to repay hundreds of thousands of pounds of taxpayers’ money in expenses.

The controversial issue returned with a vengeance with up to 500 MPs – including Gordon Brown — expected to be told to justify their claims or pay back the money.

It follows a probe by Sir Thomas Legg, who was charged by the Prime Minister to audit all MPs’ expense claims over the last five years.

He has sent every one of the 646 MPs an official letter outlining whether there are any question marks over past claims.

Shropshire MPs Daniel Kawczynski (Shrewsbury and Atcham), Mark Pritchard (The Wrekin), David Wright (Telford), Owen Paterson (North Shropshire) and Montgomeryshire MP Lembit Opik were still waiting to learn today what Sir Thomas had to say about their claims.

Ludlow MP Philip Dunne said: “Having not claimed for the second home allowance since elected in 2005, I would be surprised if I got a letter.”

Sir Thomas has given MPs three weeks to repay the cash, justify they were entitled to it, or challenge demands. Up to 20 are expected to be told to pay back tens of thousands of pounds.

However, it is believed scores of MPs have made it clear they have no intention of paying back the cash, while some are considering legally contesting claims.

And Sir Stuart Bell, who sits on the committee that will decide how MPs who abused the system are punished, said many MPs thought Sir Thomas was acting beyond his remit.

He said: “I think many MPs may feel he’s not respecting decisions made by the fees office in accordance with the rules at the time.”

But Mr Brown, who claimed £6,577 for cleaning his second home, warned it would be unwise for MPs to refuse to pay back the cash.

His comments came as Parliamentary Commissioner for Standards, John Lyon, was set to publish details of a separate investigation into former home secretary Jacqui Smith’s second home expenses.

By London Reporter Sunita Patel