Parliament's moral authority has slumped to its "lowest ebb in living memory", former Archbishop of Canterbury Lord Carey has said.
Lord Carey told the News of the World that recent leaked reports about MPs' expenses had shaken trust in politics.
He said the revelations had exposed the "clawing greed" at the heart of Westminster's "culture of abuse".
Some MPs who were the subject of Daily Telegraph articles about expenses have insisted the stories were inaccurate.
The Telegraph has published details of expenses claims by the prime minister, government ministers, other Labour backbenchers and junior ministers and two Conservative MPs in recent days.
They have all responded by saying they were operating within the rules, and a number have questioned the accuracy of some of the stories.
In the News of the World, Lord Carey questioned whether public trust in politicians could ever be restored following the exposure of "systematic abuse" of the expense system.
He said many MPs had come to see their allowances as a "right rather than a privilege", and contrasted the spectacle of ministers "cringingly" justifying their expenses while their constituents suffered as a result of the recession.
This threatens to be the straw that finally breaks the camel's back
"It is not just the clawing greed of painstaking claims for such minor items as tampons, barbecue sets and bathrobes, but also the egregious way some have transferred allowances from one second property to another - enabling them to refurbish homes at public expense, then sell them for profit," Lord Carey added.
"Coming at a time of financial crisis and political betrayal of the Gurkhas, this threatens to be the straw that finally breaks the camel's back."
Lord Carey acknowledged that many MPs had "honour and integrity". He said he had recently met Gordon Brown and been convinced the prime minister was driven by "a desire to serve his country".
But he said the affair had demonstrated that politicians could not police themselves, and called for an independent body to oversee any proposals about reform to the expenses system.
Also in the News of the World, a poll by ICM of 508 adults suggests that more than two-thirds of respondents said they believed the expenses revelations had damaged the prime minister.
Some 89% believed the reputation of parliament had been tarnished, and 91% said they wanted expenses records to be published in full straight away.
On Sunday Communities Secretary Hazel Blears was among those under pressure, after she confirmed she did not pay capital gains tax on profit from the sale of a London flat.
The property was registered as her main residence with the Inland Revenue for tax reasons, while at the same time she was claiming second home expenses from the Commons authorities for the same flat.
Minister Hazel Blears responds to pressure over the sale of her London flat
A spokesman for Ms Blears said she had complied with both Commons and tax rules and had no liability for capital gains tax on the sale of the south London property.
She later said she understood "why the public hates this", adding that ordinary people should be drafted in to help come up with a fairer system.
The newspaper also reported details of second home claims for London properties by Sinn Fein MPs, who do not take their House of Commons seats.
The party denied the MPs had done anything wrong because they regularly travelled to London on parliamentary business and used the accommodation they rented.
And Work and pensions minister Kitty Ussher had received - legitimately - more than £22,000 over a 12-month period towards improvements to her home, the paper reported.
PM story clarified
Among those MPs to earlier hit back at the reports was immigration minister Phil Woolas, who threatened legal action over allegations he claimed for women's clothing, nappies and comics.
Health minister Ben Bradshaw said the Telegraph's report about his expenses was factually wrong, and Labour backbencher Margaret Moran said allegations she claimed more than £20,000 for a house 100 miles from her constituency were "inaccurate" and "probably actionable".
On Friday the Telegraph published details of 13 Cabinet ministers' expenses. It plans to publish further revelations about MPs from other parties in the coming days.
The Telegraph has issued a clarification over an earlier story about Gordon Brown paying his brother for a cleaner they shared. The paper stressed there had never been any suggestion of impropriety on the part of Mr Brown or his brother.
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