Gordon Brown and David Cameron urged their MPs on Tuesday to disclose details of family members they employ, in a bid to dispel an air of sleaze surrounding parliament.
The prime minister told Labour MPs to publish as soon as possible a list of relatives paid out of their allowances and backed a root-and-branch review of the current expenses system.
Earlier, Cameron ordered the Conservative front bench to disclose details of how they spend their allowances and which relatives they employ.
The moves come after Cameron ousted Tory MP Derek Conway from the parliamentary party last week following the disclosure he used taxpayers' money to pay a son for work he apparently never did.
Brown, Cameron and other MPs feel they must act urgently to counter a growing public perception that MPs are abusing taxpayers' money and are bending the rules.
"The public need to be reassured that all taxpayers' money used to support members in their work both in parliament and their constituencies has been properly spent and accounted for," Brown said in a letter to House of Commons speaker Michael Martin.
Martin has ordered a review of the expenses system in the wake of the Conway scandal.
In an apparent dig at Cameron's earlier announcement, Brown said he favoured a "deliberative and orderly process" rather than a "quick fix" to the expenses problem.
RIGHT TO KNOW
Cameron said the Tory front bench in July will have to publish details of expenses incurred between April and June and expenses will then be published annually in July.
He said he hoped other Tories would follow the lead on expenses that will be set by the 96 members of his front bench.
"The public do have a greater right to know about the use of expenses and allowances," he told a news conference. "Every member of parliament has to ask themselves: is this something I am happy to defend to my constituents, to the press?"
Cameron will ask his front bench team to complete a form that explains how they spend their allowances, including how much they pay family members, within a salary band, and how much they claim for housing and utilities on second homes.
The measures would be in addition to any changes recommended by Martin's review, which is expected to report in the Autumn.
Despite Conway's transgressions, a poll on Tuesday showed Labour's image was suffering more than the Tories from sleaze.
The Populus poll showed the Tories' popularity had risen three points to 40 percent, while Labour was down two points to 31 percent.
It found that in the public's mind Labour was more closely linked with sleaze allegations than the Tories, although it did find that sleaze was linked to both parties.
In another setback for Brown and Chancellor Alistair Darling, the poll also found Cameron and his shadow chancellor George Osborne had stronger ratings for economic competence.
