The man in charge of administering expenses in the House of Commons has admitted that he thinks MPs are willing to exploit the system.

Andrew Walker, the director of finance and administration, also conceded that until 2006 MPs had been able to remortgage their house if they wanted cash in hand — even though the taxpayer meets the cost of the mortgage. He said that now MPs could only remortgage if the move was sanctioned by the finance department. Valid reasons include wanting to carry out building works on the property, he said.

A former MP alleged yesterday that his colleagues had routinely put in for the maximum allowances by claiming for “food”, a category that does not need receipts.

Richard Allen, a Liberal Democrat, who ran Nick Clegg’s campaign for the party leadership, said: “In the not so distant past \, there were no limits on what could be claimed for food. They could claim whatever they liked against the additional costs allowance and many did, simply putting in a claim for a twelfth of the annual sum each month.”

Mr Walker defended MPs’ ability to claim up to £400 a month in food without receipts — a limit introduced in 2004 — saying that Parliament had voted on the arrangement and the system was subject to checks from the National Audit Office.

“If Members didn’t eat they might not be able to perform their duties,” he added.

He argued against the release of the “John Lewis spreadsheet” — which the expenses department uses to determine the maximum prices that MPs can spend on items such as washing machines and televisions for their second home. Mr Walker said that he had no argument in principle with the public seeing the spreadsheet, but feared MPs would automatically use it to buy goods costing close to the maximum.

“My concern isn’t to withhold the form from the public but because it’s a guide to staff. My concern is that the maximum price will become the going rate.”

Mr Walker was speaking at the second day of a Freedom of Information tribunal brought by The Sunday Times, The Sunday Telegraph and Heather Brooke, an information campaigner, to be given more details about MPs’ second home allowances.

He again defended the decision not to put more details into the public domain, saying it could encourage “prurient interest and curiosity”, citing the publication of details of a quad bike bought on expenses by David Maclean, a Conservative MP with a disability.

He also was unable to explain why Ben Wallace, a Conservative MP who published all his expenses online last weekend, had included a hotel bill when he also claims for a second home. The previous day, Mr Walker had suggested that only those MPs who lived at the other end of the country would claim for hotels if they were unable to complete their journey home in a day.

Asked about Mr Wallace’s hotel bill, he said: “I have no idea. For all I know that claim was rejected.”

Mr Walker defended the right of ministers with grace-and-favour apartments also to claim the additional costs allowance for a second home. Ministers often already own a second home when they are appointed, and some do not use the grace-and-favour apartments, he argued.

Ms Brooke said yesterday: “His testimony showed utter disregard for the public by saying that the only way MPs are accountable is in the ballot box. This is flawed because they are not getting the information they need to make an informed decision.”

A verdict is expected at the beginning of next month.

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