In an interview with The Times, Sir Philip Mawer said that the sharp differences in expenses claims among MPs were not easily explicable. He urged stricter rules to restore confidence.

MPs should provide receipts for any claim above £50, rather than £250, and ministers with grace-and-favour homes should no longer have constituency houses funded by taxpayers as well, he said.

Tighter rules were required for MPs’ use of free stationery and postage, and for budgets that allow them to produce newsletters and websites, Sir Philip said. He called on politicians to cut their bills for free travel. “The degree of variation in the spend on stationery and allowances, and in some aspects of the travel regime, are not easily explicable,” Sir Philip said. “It is so marked that it is bound to give rise to questions about Members’ practice.”

He has written to the Senior Salaries Review Body, which is conducting its three-yearly study of MPs’ pay and allowances, proposing a series of changes and he expects to give evidence to its inquiry in person shortly. It will report this year and any changes will be voted on by the Commons.

He also advocated fresh guidelines on the use of parliamentary facilities for party fundraising and other political purposes, which is the subject of two inquiries he is conducting into the events hosted in Commons dining rooms by David Cameron and several other senior Tories. “There is clearly a need to try to define things more clearly for the benefit of members as well as the public.”

Sir Philip, the Parliamentary Commissioner for Standards, said that concerns about MPs’ expenses had overtaken those about outside earnings as an issue of public concern, despite past moves to plug loopholes. “The focus has shifted,” he said. “Looking back over the ten years or so that this current regime has been in operation, the spotlight initially was on cash-for-questions, that is paid advocacy. Then the spotlight shifted towards failure to register or declare interests. Now the spotlight is on allowances.”

Sir Philip, previously the secretary-general to the General Synod of the Church of England, said that he had received 23 complaints last year, compared with 42 a year earlier.

He first proposed that MPs should produce receipts for larger expenses claims after his inquiry into Michael Trend, a former Tory MP who falsely claimed £90,000 in housing costs. The threshold was set then at £250 for all claims other than hotel bills.

In the Times interview, Sir Philip said: “That figure is too high. While there is a balance to be struck between being over-nannying and requiring members to produce receipts for every penny they spend, which I think in the midst of a busy life would be difficult, I do think the figure ought to be significantly reduced.”

Similarly, he said that the MPs’ housing allowance should be amended to require politicians to maintain at least one home themselves rather than from public funds. This would hit ministers with grace-and-favour homes in London.

“One principle, which must be observed, is that any member, whether a government minister or not, ought to be expected to pay for at least one house,” he said. “There has been some concern in the past that, in the case of ministers, they may have a provided home, which they are not paying for, they are claiming a parliamentary allowance on a home in the constituency and they are renting out the flat in London, which they occupied before they became a minister.”

MPs have approved an annual communications allowance of £10,000 for websites, newsletters and other ways of keeping in touch with voters. Sir Philip said that this should be accompanied by reform of the free postage system.

There were accusations that some Labour MPs defending marginal seats used the free stationery and postage services provided by the Commons, in effect, to campaign at public expense. Some claimed about £25,000 on postage and more than £12,000 on stationery.

Sir Philip admitted that, despite his concerns at variations in MPs’ travel claims, it was more difficult to tighten those rules without unduly restricting Members’ work. Instead he called on MPs to compare notes and reduce the amount that some claim.

What MPs can claim for

1 Eric Joyce (Falkirk) Lab £174,811

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