Liberal Democrat leader Nick Clegg today warned that he would not prop up a Labour government which had collapsed to third in the popular vote.
He said Britain's "potty" electoral system meant it was possible that Labour could get fewer votes than both the Lib Dems and the Conservatives on May 6 and still emerge as the biggest party in a hung parliament.
In an interview with BBC1's The Andrew Marr Show, he made clear that there was no question in those circumstances of the Lib Dems combining with Labour to enable Gordon Brown to hang on to power.
"It is just preposterous the idea that if a party comes third in the number of votes, it still has somehow the right to carry on squatting in No 10," he said.
"I think a party which has come third - and so millions of people have decided to abandon them - has lost the election spectacularly (and) cannot then lay claim to providing the prime minister of this country."