Sir Menzies Campbell's move to become Liberal Democrat leader received a major boost today when the former leader Lord Ashdown endorsed his campaign.
The stand-in leader is the only challenger so far to succeed Charles Kennedy, who was forced out by MPs at the weekend after confessing to a drink problem.
Party president Simon Hughes and home affairs spokesman Mark Oaten are both widely expected to join the race.
But Lord (Paddy) Ashdown, still a very popular figure with activists, said Sir Menzies "would offer something which frankly neither of the other main candidates are able to".
His unusual intervention came as the party's executive committee prepared to meet tonight to draw up detailed plans for an election.
Mr Hughes, whose chairs the committee, said he would announce within a week whether he intended to enter the contest.
But the party also faced a stark warning from Mr Kennedy that his departure risked sparking the sort of infighting that hit the Tories in the wake of Margaret Thatcher's ousting.
Speaking on BBC Radio 4's Today programme, Lord Ashdown said Sir Menzies, who has been backed by 23 of the party's 62 MPs, was "highly respected".
"He is highly respected, he is a man of unimpeachable integrity, he can offer a serious and heavyweight proposal for the British people representing Liberal Democrat policy and I think that far outweighs other factors."
Lord Ashdown's intervention will come as a surprise to many. Former leaders are normally reluctant to come out in favour of a candidate in a leadership contest.
"Last time I thought it improper that as the departing leader of the party I should support anybody," he said.
"I think that is probably right. But now that I am the last leader at one remove I suppose I can come among you unmuzzled and say who I am going to support. The short answer is Menzies Campbell."
The party had the "brightest" bunch of young MPs of any party but they were not yet ready to take on the top job, he said.
Sir Menzies would offer the British public an alternative that had "weight and substance and seriousness" in a political debate increasingly obsessed with "modishness and flim-flam".
Sir Menzies' age - he is 64 - was not "much of a factor", Lord Ashdown said - adding it would be wrong to "force" an election.
Mr Kennedy, who initially called an election to prove he had the support of grassroots members, has called for a contest not a coronation to ensure the membership has a say in who succeeds him.
Mr Hughes has so far refused to rule himself in or out of standing as leader and insisted the timetable must be set first.
"I will then make a decision based on what is in the best interests of the party and which ties in with what I think I ought to do," he said.
"I will make an announcement within seven days of tonight ..."
Mr Hughes rejected the idea an election could spark a "civil war" in the party as rival wings vie for supremacy.
He represents the party's left-leaning social democrats, while Mr Oaten, 41, would be a champion of the economic liberals.
Although on the right wing of the party, Sir Menzies, like Mr Kennedy, is seen as a figure who could straddle the two camps.
"That's absolutely the opposite of the case. Contested elections are healthy for democracy. The Conservative Party had one, they saw it did them no harm," Mr Hughes said.
"We will have one, I hope. I am sure it will do us no harm. The members can participate, the public can watch and listen, people will become interested.
Sir Menzies is the bookies' favourite and his age makes him a popular choice with many young and ambitious MPs.
He would be unlikely to stay on past the next election, when he is likely to be 70, giving them time to build support for their own bids.
The party's one member, one vote constitution means a ballot of the party's 73,000 members.
Baroness Williams - former MP Shirley Williams and an ex-Lib Dem leader in the House of Lords - said Sir Menzies had so much support it would be "a brave man or woman" who stood against him.
She told BBC Breakfast: "The trouble is you can't force somebody to stand in what is likely to be a very, very hard race to win against Menzies Campbell.
"There isn't any way you can force a contest, that's quite obvious, and I think Menzies now has so much support that it would be a brave man or woman who would stand against him with any certainty that they might be able to win."
Local government spokeswoman Sarah Teather, one of the key movers behind the statement issued by Lib Dem frontbenchers on Friday asking Mr Kennedy to consider his position, called on other candidates to come forward.
Although she supported Sir Menzies' bid, she said it was "essential" to involve ordinary party members and added that his election was not a foregone conclusion.
In an interview with Aberdeen's Press And Journal newspaper, Mr Kennedy said the departure of a leader with "broad support" should sound warning bells for the party.
The Conservatives were plagued by in-fighting after Mrs Thatcher was replaced by John Major in 1991 after losing the support of MPs despite being hugely popular among the membership.
He said: "I am convinced that we should avoid that in the Liberal Democrats, but the danger is there when something like this can happen to a leader who has broad support."
He thanked members of his Ross, Skye and Lochaber constituency for their support over the past week and said there was no need for them to be "downhearted" as he was not.Reuse content