Nick Clegg's leadership of the Liberal Democrats has been endorsed by Paddy Ashdown, as the party elder hit out at the "personal manoeuvring" of other senior figures.
Lord Ashdown said the Deputy Prime Minister had challenged the Lib Dems to move from a party of perpetual opposition to one willing and able to grapple with the hard choices of government.
Writing in the Guardian, Lord Ashdown urged his party, which he led between 1988 and 1999, to continue with the job that it began in 2010 when it endorsed Mr Clegg's decision to enter into a coalition with David Cameron's Conservatives.
Rumblings about a challenge to Mr Clegg's leadership of the Liberal Democrats have grown since House of Lords reform was abandoned over the summer. Lord Oakeshott, an ally of Business Secretary Vince Cable, suggested the party consider a change of leadership before the next election.
But Lord Ashdown said: "We will be judged at the next election by one fact and one fact only. Whether we have had the mettle to stay the course in delivering effective government for our country at a time of crisis. That is the only thing that matters. All the rest is the froth.
"Nick challenged us to leave our comfort zone and make the change from a party of perpetual opposition to one capable of carrying the burdens of government.
"Without Nick, that decision would never have been made, and the historic opportunity to show who we really are would never have existed. It is the job of our leader to take us into government. I failed; Nick has succeeded.
"Of course, now there are plenty of easier courses on offer. In tough times there are always petty ambitions to be aired, the kind suggestions of our enemies to be ignored, and helpful comments from the sidelines to be endured.
"The right thing for Liberal Democrats to do now is to continue to do what we have done so well so far. Concentrate on the job we set our hands to under Clegg's leadership. Nothing else."
Lord Ashdown said his party had grown used to ignoring opinion polls, which he said had consistently underestimated Liberal Democrat support mid term for more than a decade.