Commons Leader Harriet Harman has refused to rule out exempting MPs from Freedom of Information laws despite calls by Cheltenham's MP.

Martin Horwood was among MPs to press Ms Harman for assurances during a parliamentary debate on the subject of members' expenses.

It came as Ms Harman confirmed that receipts detailing MPs' expenses since 2004 will be published once they are processed by House of Commons authorities.

FOI requests relating to the receipts would be complied with at a cost of around £2 million, she said, but sensitive information would be censored.

Confirmation that the receipts will be released came after the Government opted not to press ahead with controversial plans to exempt MPs from FOI laws.

However, regular itemised publication will not form part of a new regime for MPs' expenses which Ms Harman said would prevent abuse and assure constituents that "public money is being properly spent".

Instead, the proposals extend the automatic reporting of MPs' expenses from 14 to 26 categories.

However, Ms Harman repeatedly refused to rule out future attempts to exempt MPs from FOI legislation when pressed by Mr Horwood and other opposition MPs.

The Lib Dem MP said: "If the new regime is going to be as open as we would all want, surely there will be no need to exempt MPs from the Freedom of Information legislation."

Ms Harman said it was important no previous Ministers had taken such action because it had allowed for MPs' addresses to be censored on security grounds.

Mr Horwood said later: "This was a very disappointing reply. At the very moment when we are about to reveal details of MPs' expenses in more detail than ever before, the Government risks undermining public confidence yet again by giving the impression we are still trying to wriggle out of full disclosure. It is time they accepted the inevitable and agreed to MPs being subject to the same rules as everyone else."

There has been intense focus on MPs' expenses following a series of scandals including former Tory MP Derek Conway using his allowance to pay his son for work in Westminster while he was studying at university.

There has also been controversy over the "John Lewis" list which detailed acceptable levels of spending for household items.

Ms Harman made a bid to exempt MPs from the FOI laws last week while attention was focused on expansion of Heathrow Airport.