Liberal Democrats will fight the 2015 election on a message that only a Government including the third party can be trusted to deliver a recovery that is fair and sustainable, Nick Clegg said on Sunday.
A return to single-party government after five years of coalition would mean "squandering" the sacrifices made in the period of austerity, he said. A majority Labour government would "wreck" the recovery, while a Conservative-only administration would deliver "the wrong kind of recovery" by allowing the proceeds of growth to go to the rich.
The Lib Dem manifesto for the 2015 poll will be explicitly written with post-election negotiations in mind - identifying the policies which they are ready to "die in the trenches" for, as well as others which are open to compromise in coalition talks - said Clegg. And he challenged the other parties to do the same.
One red line for any negotiations is almost certain to be measures to take anyone earning the minimum wage out of income tax by raising thresholds to around £12,500, which Clegg said would be a "signature tune" of the Lib Dem campaign. He hinted that the Lib Dems' cherished "mansion tax" on residential properties worth over £2 million was also like to feature, though he insisted final decisions will not be taken until nearer the election.
Despite going into the Lib Dem annual conference in Glasgow with his party trailing at 9% in recent opinion polls, Clegg was bullish about the prospects of retaining a share of power in a hung Parliament after the general election.
"Our message to the British people in 2015 will be essentially this: We will say 'We've done very good things in Government - let us finish the job, but finish the job fairly'," Clegg told BBC1's Andrew Marr Show.
"It is my genuine belief that if we go back to the bad old days - not of coalition or balanced politics, but of either the left or the right dominating government on their own - you will get a recovery which is neither fair nor sustainable.
"I think Labour would wreck the recovery, and under the Conservatives - who don't have the same commitment to fairness which we do - you would get the wrong kind of recovery."
Coalition was "much better than either the left or the right messing things up on their own all over again", he said.
Clegg said there had been no discussions with Tories about continuing their coalition, insisting that talks with either major party must wait until the electorate has had its say. He appeared to indicate that - as in 2010 - he would speak to the largest party first, telling interviewer Andrew Marr that whoever gained the "clearest mandate, the most votes and the most seats" in a hung Parliament had the democratic right to attempt to form a government.
Delegates in Glasgow gave the party leadership more room for post-election negotiations by rejecting an amendment which would have committed the party to opposing new nuclear power plants.
In a historic moment overturning long-standing opposition to nuclear power, party members voted by 230 to 183 in support of new plants in "limited" circumstances after Energy and Climate Change Secretary Ed Davey warned it would be "reckless" to rely on coal, gas and renewables.
Meanwhile, senior Cabinet minister Danny Alexander urged delegates not to insist on nuclear disarmament in a debate on Tuesday, arguing that his own proposals for a scaled-back Trident deterrent provided a "credible and deliverable" alternative with a genuine chance of being accepted by other parties in coalition discussions.
Both Clegg and Alexander delivered a rebuff to Business Secretary Vince Cable over his suggestion that Chancellor George Osborne's flagship Help to Buy scheme could be confined to areas where the housing market is stuck in the doldrums, to avoid stoking up a bubble in London and the South-East.
"What Vince said is absolutely right, that given the sorry history of asset bubbles in the British economy, we need to be vigilant, said the Deputy Prime Minister
"Of course we are going to be vigilant, but as Vince will be the first to acknowledge, we are nowhere near yet the peak of that unsustainable housing bubble. Clearly in parts of the country - notably central London - the housing market is now marching forward, but you can't set a national policy... based only on what happens in Kensington and Chelsea. You have to think about all the other households."
Alexander said the concerns of the Business Secretary - who represents Twickenham in south west London - would simply not be recognised across most of the rest of the country.
"We are a million miles away form a housing bubble in this country," he told Sky News's Murnaghan programme . "I don't think we should allow the tail of central London to wag the dog of this policy."
Labour deputy leader Harriet Harman said: "Nick Clegg is desperately trying to distance himself from the failures of David Cameron's Government.
"The truth is that he has broken his promises, and backed the Tories all the way. Nick Clegg and his party must take responsibility for their Government's failure which has caused the cost-of-living crisis families are facing."
Former Lib Dem MP Chris Huhne said that Clegg was "probably" safe from removal as party leader before the general election, and pedicted the Lib Dems will do better in 2015 than their current poll ratings suggest.
Huhne proposed that Lib Dems could regain some of the support among students lost due to their tuition fee U-turn by offering to waive fees for state school pupils with three A grades at A-level.
Writing on the Guardian's website, Huhne said that Clegg's ratings were "well below the territory that fashioned an ejector seat for William Hague, Iain Duncan Smith and Sir Menzies Campbell".
But he added: "For all that, Nick Clegg is probably safe until the general election, and certainly until after next May's local and European elections.
"Crucially, his ratings are not much worse than Ed Miliband's and there is the added consolation for him, though not for the voters, that all three main party leaders are unpopular."
Huhne added: "On average in each Parliament since 1987, Liberal Democrat support rose by 8.5 percentage points between the low point as measured by polls and the general election. This bounceback was sometimes big and sometimes small, but it has been inexorable.
"The 2010 election was not a flash in the pan: it was the culmination of a 30-year breakdown in two-party politics. If the Liberal Democrats hold their nerve, they will do better than most people think at the next election and may well be in the next government."