Deputy Prime Minister Nick Clegg today insisted he would "never, never, never" join the Conservatives, saying: "I will be carried out in my coffin as a card-carrying Liberal Democrat".
Mr Clegg's forthright denial that he is tempted by a move to David Cameron's party came as Labour leader Ed Miliband made moves to woo left-leaning Lib Dems to defect, while Conservative backbenchers suggested that those on the right of the party should consider taking the Tory whip.
The Liberal Democrat leader was coming under massive pressure to reassert his party's identity within the coalition Government after his humiliating defeat on electoral reform and in elections to English councils, the Scottish Parliament and the Welsh Assembly.
But he insisted that the Lib Dems had "a platform from which we can recover" after scooping one vote in seven in Thursday's elections.
Asked on BBC1's Andrew Marr Show whether he could ever envisage joining the Conservatives - and perhaps taking a Tory peerage - Mr Clegg replied in shocked tones: "Join the Conservatives? No, never.
"I am not a Conservative - never have been, never will be. Never, never, never.
"I am a Liberal Democrat to my core. I will be carried out in my coffin as a card-carrying Liberal Democrat."
Mr Clegg denied he had made a strategic error by allowing his relationship with Mr Cameron to appear so warm and close in the early days of the coalition, when they famously took part in a joint press conference in the Downing Street rose garden that was described as a "love-in" by many observers.
"I think it isn't about the chemistry or dynamic between one individual and another," he told the BBC. "It is what is in the long-term interests of the country."
And he added: "We have had a very clear, businesslike partnership in what is a coalition Government in which we work in the long-term interests of the country and in which we retain, but don't diminish, our own identities.
"People want us to maintain and not lose our identities. I don't think we have, and I have now got to prove we haven't.
"That is exactly what will happen in the weeks and months to come."