The next Liberal Democrat leader must be someone who defied Nick Clegg over student fees, one of the party's few remaining MPs has declared in an apparent endorsement of Tim Farron.
Mr Clegg resigned after what he conceded was a "crushing" General Election in which all but eight seats were lost, cutting short the political ambitions of a succession of high-profile figures such as Vince Cable, Danny Alexander, Ed Davey and David Laws.
Among the survivors, left-leaning former party president Tim Farron and close Clegg ally Norman Lamb - health minister in the Conservative-led coalition government - were favourites to take on the task of attempting to rebuild.
With many blaming five years of power-sharing compromises for the catastrophic wipe-out at the polls - not least the notorious abandonment of a 2010 pledge not to raise fees - Greg Mulholland said only a rebel on that issue could take the party forward.
He said the controversy, along with backing NHS reforms and the so-called "bedroom tax" was one of "three fatal errors" made by Mr Clegg after he took the "right decision" to join forces with the Tories.
"The 2010 failure to ensure no Liberal Democrat MP voted against a rise in fees was catastrophic. Now we need a leader who voted against," he said.
Of the eight remaining MPs, only Mr Farron - who retained his Westmorland and Lonsdale seat - and Mr Mulhollland voted against the rise in fees.
But the Leeds North West MP has ruled out a tilt at the top job.
Asked if he would be tempted by the vacancy, he told ITV News: " No, very easy answer. My priority, apart from my constituents, in terms of the party, is rebuilding it locally and rebuilding it nationally. That is something that I, and we, will do.
"Clearly those of us who have been re-elected will have to talk about how best we can work together and how we should operate going forwards over the next few years."
In an emotional speech to activists Mr Clegg, who held on to his own Sheffield Hallam seat with a much-reduced majority, said: "I always expected this election to be exceptionally difficult for the Liberal Democrats given the heavy responsibilities we have had to bear in government in the most challenging of circumstances.
"But clearly the results have been immeasurably more crushing and unkind than I could ever have feared. For that, of course, I must take responsibility."
Relinquishing the reins after seven years, he insisted there was a "way back" and promised his party it "would win again".