Nick Clegg: "Question marks" over the Chancellor's finances
The Liberal Democrats have called on Chancellor Alistair Darling to be sacked over his expenses, saying "his moral authority has vanished".
Mr Darling has been accused of "flipping" his second home four times in four years and claiming public money to help complete his tax returns.
Mr Darling said the allegations were "untrue" and Business Secretary Lord Mandelson called them "cheap jibes".
But Lib Dem leader Nick Clegg said Mr Darling had to be beyond reproach.
"As chancellor, Alistair Darling occupies a very special position in government.
"He needs to enjoy the public's trust when it comes to issues of financial probity, of money, of managing our nation's finances," he told BBC Radio 4's Broadcasting House.
"And given that very unique responsibility that he has, it's simply impossible for him to continue in that role when such very major question marks are being raised about his financial affairs."
Mr Clegg refused to back down or apologise when challenged about his call for Mr Darling to be sacked, telling the BBC News channel people "at the top of government had to take responsibility for what has gone wrong".
He urged the chancellor to refer his expenses claims for scrutiny by "someone independent".
He was backing comments by Lib Dem Treasury spokesman Vince Cable in an article for the Mail on Sunday, in which he accused Mr Darling of being "caught with his fingers in the till".
There is not a scintilla of truth in the idea that I might become chancellor
"He doesn't explain. He doesn't apologise. He just blames his colleagues for not stopping him. His moral authority has vanished. He must go, now," wrote Mr Cable.
"We need a chancellor focusing on the national accounts rather than his own. There are some urgent economic questions to address."
Mr Cable dismissed suggestions he could be invited to join the government as part of a bid by Labour to restore public faith in politics.
"I would not agree to be co-opted into a Labour government in its dying days.
"There is not a scintilla of truth in the idea that I might become chancellor.
"I am part of Nick Clegg's team and that is where I intend to remain.
"This kind of arrangement might have been possible in the early days of Tony Blair's government, but not now. What we need now is an election."
Mr Darling was reported by The Daily Telegraph to be among ministers who paid accountants thousands of pounds of public money to complete their personal tax returns, his own bills coming to £1,400 over two years.
Ministers insisted that the accountancy bills were in relation to their work as MPs and that the claims were allowable under the Commons rules.
That's pure politicking by Nick Clegg and by Vince Cable, and frankly it's beneath both of them to start hurling around cheap jibes like that
Lord Mandelson, business secretary
It was also reported that Mr Darling "flipped" the location of his second home four times in four years, allowing him to claim thousands of pounds towards the cost of his Edinburgh home and a London flat.
In a statement, Mr Darling's office said: "The allegations made by Mr Cable are untrue.
"As Mr Darling consistently explained he paid for personal tax advice himself.
"The accountant's fees claimed were for preparing his office accounts to ensure the correct amount of tax was paid. That's an allowable claim. The accountant's fees were fully declared for tax purposes and he paid tax on the benefit.
"The allegation that he changed addresses for personal gain is untrue. He changed the designation of his second home when his circumstances changed in accordance with the rules.
"He also pays tax on the benefit of living in Downing Street and pays the council tax there."
The Sunday Times is reporting that Prime Minister Gordon Brown is ready to sack Mr Darling as chancellor and replace him with schools secretary and close ally Ed Balls in a gamble to restore Labour's political fortunes.
In an interview with BBC One's Andrew Marr show, Mr Brown refused to be drawn whether he would reshuffle key ministerial posts after Thursday's European and local elections, which are expected to see Labour take a hammering.
Business Secretary Lord Mandelson also refused to speculate on Mr Darling's future - and whether he would be replaced by Mr Balls or even Vince Cable - as chancellor.
When tackled about the issue on BBC One's Politics Show, Lord Mandelson said: "I'm not unfortunately in a position to pick the Chancellor of the Exchequer of this country, I'm not the prime minister."
He said he had "worked very well with Mr Darling," and added: "If it is the prime minister's choice that I should continue to do so, I'll be very happy to do that."
He later hit out at the two senior Liberal Democrats calling for Mr Darling to be sacked.
"That's pure politicking by Nick Clegg and by Vince Cable, and frankly it's beneath both of them to start hurling around cheap jibes like that," he told BBC Radio 4's The World This Weekend.
Climate Change Secretary Ed Miliband also defended the chancellor, telling Sky News: "I think Alistair Darling was doing absolutely right, I think he complied with all the tax rules."
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