Nick Clegg has been forced to spell out his intention to continue to lead the Lib Dems following reports senior MPs are positioning themselves as possible successors
The Deputy Prime Minister will serve a full term as Liberal Democrat leader in the next parliament if the party remains in power, he confirmed on Sunday.
A spokesman for Clegg said that "if the Liberal Democrats are back in government again Nick Clegg intends to serve a full term".
But, with the party trailing in fourth place in the opinion polls, there was less certainty about the fate of Clegg's leadership if the 2015 general election contest did not result in another coalition.
The spokesman said: "Our entire focus is on delivering Liberal Democrat priorities in government and then getting Liberal Democrats back in government in 2015 as the only party capable of building a stronger economy and a fairer society.
"Nick Clegg is very much enjoying his role as both Deputy Prime Minister and leader of the Liberal Democrats. He is only 47.
"It is for the British people to decide if the Liberal Democrats are back in government again. But if the Liberal Democrats are back in government again then Nick Clegg intends to serve a full term."
Asked what would happen if the Lib Dems were not returned to office the spokesman said: "Nick Clegg's entire leadership has been about getting the Liberal Democrats into government. People said he wouldn't be able to do it but he did in 2010.
"People will say he won't be able to do it again in 2015 but we have every confidence he will."
The focus on Clegg's future came as he used his closing speech at the Lib Dem spring conference in York to insist that the party must remain in government to avoid the UK being dragged backwards by the Tories and Labour.
Treasury Chief Secretary Danny Alexander faced questions about his leadership ambitions following reports he was "on manoeuvres" against a potential rival for the top job, Business Secretary Vince Cable.
Alexander was asked about claims he was after the top job in the party on Sky News's Murnaghan programme.
He said: "There's no vacancy; I hope there isn't a vacancy for many years to come. I think Nick Clegg is doing a fantastic job, I've got a big job to do to make sure that we continue the policies that are making our economy recover, delivering those tax cuts and getting across to the British people that this economic recovery and those income tax cuts wouldn't be happening without the Liberal Democrats in Government."
He added: "I think that is more than enough on my plate for the moment."
Speaking on BBC Radio 5 Live's Pienaar's Politics, Lib Dem Cabinet Office Minister David Laws dismissed suggestions that Clegg was a "liability" for the party, which has been limping along in the polls, often struggling to get beyond single-figures.
"I'm sure that Nick will lead the party into the next general election campaign and right through it," he said.
"I think that any Lib Dem leader that was having to take lots of tough decisions in a coalition, not least with the Conservative Party, would have that reflected in the opinion poll ratings - it comes with the territory of being associated with taking difficult decisions.
"But I believe that Nick is the right person to lead us into the next general election, I believe he will do and I believe that people will actually respect what he's achieved as Deputy Prime Minister and leader of our party over this Parliament, where he would have helped deliver the recovery, the reduction of public borrowing and, you know, a fairer country.
"Some of those big things in our manifesto: the pupil premium, the tax allowance - things that the Prime Minister said couldn't be delivered because they were too expensive - we've achieved those in government, some of the biggest most important things this coalition has done in policy terms are the things that the Liberal Democrats delivered."
"And if you think what are the Conservative policies, actually there's very little that's as significant as the Lib Dem policies that this government has implemented."
The questions about Clegg's future drew attention away from his speech, in which he said the next parliament would have to focus on the "reconstruction and renewal" of the UK, with only the Lib Dems able to act as "guardians of a modern, open and tolerant Britain".
Ahead of the European elections and his head-to-head debates with Nigel Farage, Clegg said he was taking on the "politics of blame" and looking to "the future, not the past".
Clegg delivered a robust defence of his party's record in Government and claimed the Lib Dems were responsible for the economic recovery.
He told activists in York: "There is still a long way to go and many people are still feeling the squeeze.
"But after a period of grave uncertainty, the British people can finally see the light at the end of the tunnel."
He added: "Don't let anyone airbrush out our role. Thanks to the heroic efforts and sacrifices of millions of people we have been able to pull this country back from the brink. Under extraordinary pressure we have achieved extraordinary things.
"And no matter what our critics say, when the history books are written they will say that, most extraordinary of all, the country was put back on the right track by a party which had never been in government before but which had the guts and the courage to do what it took."
Despite the party's poor poll ratings, Clegg could still find himself playing kingmaker in the event of another hung parliament after the 2015 contest.
Setting out what he wanted to achieve after 2015, Clegg said: "We've been in emergency mode for the last four years, but that is slowly changing. If this parliament has been about a rescue, the next will be about reconstruction and renewal.
"If we are truly ambitious for our country, Britain's future cannot be like its past."
Turning on Labour and his coalition colleagues in the Tory party, he said: "I simply do not believe that they are up to this task."
Labour would deliver "profligacy" and "economic incompetence" while the Tories would offer "widening inequality" and "a remorseless shrinking of our public services".
He added: "And whichever way you look at it, left or right, if either of them get into government on their own, they will drag Britain in the same direction: backwards."
Clegg has gambled on characterising May's European elections as a straight contest between his party - appealing to all those who wish to retain ties to Brussels - and Ukip.
Although he did not mention Farage by name, he said: "An ungenerous, backwards looking politics has emerged in Britain.
"The politics of blame has found an acceptable face: it wears a big smile and looks like someone you could have a pint with down the pub.
"So I'm drawing a line in the sand. I am going to defend the tolerant and modern Britain we love, and I am going to start by showing people what's at stake at the upcoming European elections: do you want Britain in Europe, or out?"
He said Britain "stands tallest in the world when we stand tall in Brussels, Paris and Berlin".
In a swipe at the Tories, following David Cameron's pledge to hold an in/out referendum on EU membership, he added that while the institution needed reform "you can't change it with one foot out the door".
Clegg highlighted the "liberal qualities" of the UK's people as he told activists "I love Britain".
Listing some of the things that he cherished about the country, Clegg said he enjoyed its "spiky irreverence", the love of queuing, the shipping forecast and the restorative powers of a cup of tea.
"There are few nations as open-minded and warm-hearted as ours," he said.
"Smart, funny, compassionate Britain. Always changing, always evolving Britain. Humble enough to understand that we must work with others. Confident enough to lead."