Nick Clegg has accused the Tories of being "economically extreme" as he set out red lines for any future coalition negotiations. The Deputy Prime Minister said Liberal Democrats would raise taxes to help fill the black hole in public finances while the Conservatives would try to balance the books by "beating up on the poor".
Mr Clegg insisted that his party would block any attempts to take Britain out of the European Convention on Human Rights - a move floated last week by Conservatives. But he refused to rule out bringing down the cap on welfare payments from £26,000 to £23,000 set out by the Conservatives last week.
In an interview on BBC1's Andrew Marr Show he accused the Conservatives of announcing with "almost undisguised relish" that they would not ask the wealthiest to pay a "single penny towards completing the deficit reduction effort". The Lib Dem leader said that trying to clear the deficit without raising taxes was "economically extreme".
Asked if the Lib Dems would raise taxes, he said: "Yes, of course. We must raise taxes." Mr Clegg said changes to tax relief for the wealthiest pensioners and extending council tax bands to the most expensive properties were among the tax reforms proposed by the Lib Dems that would help fill the deficit black hole.
He added: "What we are saying is that those choices, either sticking your head in the sand or beating up on the poor, are not the choices the British people want. They want balance. They want balance between a strong economy and a fairer society and that is what we are offering."
Asked why the Lib Dems remained in government with a party they despised, he replied: "We have restrained the Conservatives from doing what they want on penalising the poor, on ignoring the environment, on trashing our civil liberties and human rights."
Pressed on whether Mr Clegg would stop the Tories reforming the cap on welfare claims in a future government, Mr Clegg said he would look at any proposals. "I'm very happy to look at things like that but I do not believe that ratcheting down the welfare cap is the answer. It's certainly not something we are advocating."
Mr Clegg said leaving the ECHR would "absolutely not" happen under any coalition involving the Lib Dems. "I think trashing human rights basically in order to cater for or to go after Ukip votes is a legally illiterate thing to do and is not in keeping with fine British traditions," he added.
Liberal Democrats have hovered around the 7% mark in the polls but plunged as low as 6% in recent days. Mr Clegg denied his party would lose a lot of seats at the next election, claiming national ratings "don't tell you much any more because the country's become so varied".
He urged the other major party leaders to stop "foot-dragging" and come to an agreement on televised debates for next year's election campaign. The Lib Dem leader - whose poll ratings soared after his widely-praised performance in the TV debates of the 2010 campaign - told Marr: "I'm pretty relaxed about the format. The broadcasters, I think, need to really determine what they want.
"I just think they were a precedent that people enjoyed. I think they enlivened the general election. I think all this foot-dragging from the other parties is a great shame. I think we should just get on with it, agree it and enjoy it."
Liberal Democrat Business Secretary Vince Cable said Chancellor George Osborne's plans for a two-year freeze on working-age benefits after the general election "go far beyond" what is needed to eliminate the deficit. Mr Cable told the Observer: "There's absolutely no way that making deep cuts in provision for the working poor is acceptable and that we can possibly go along with it. What he is suggesting goes far beyond what you need in order to achieve financial discipline."
The Business Secretary said Mr Osborne was wrong to suggest that £25 billion of cuts - £13 billion from Whitehall department spending and £12 billion from welfare - would be needed to eliminate Britain's deficit. The £25 billion Osborne talks about is way beyond actually what is necessary to achieve the thing we committed ourselves to do in the coalition agreement, which was dealing with the structural deficit," said Mr Cable.
Meanwhile, Mr Osborne's Treasury number two Danny Alexander said he was "pissed off" at the Tories claiming credit for tax cuts for low-income workers and Britain's economic recovery. The Chief Secretary to the Treasury told the Sun on Sunday: "The economic plan is just as much my plan as it is George Osborne's. It is just as much a Liberal Democrat plan as it is a Conservative plan.
"One of the things that really pisses me off is when people say this is all the Conservatives who have sorted out the economy. It isn't. I know it isn't."
Mr Alexander will today tell the Lib Dems' annual conference in Glasgow that the rise in income tax personal allowance to £10,500 - claimed by David Cameron last week as one of his Government's key successes - was "only happening because we Liberal Democrats fought for it every day in coalition".
He will say that the further increase to £12,500 in the level at which income tax becomes payable - a long-standing Lib Dem policy which was adopted last week by the Prime Minister - would only be implemented fairly if Liberal Democrats remain in government after the election.
Mr Alexander accused the Tories of lurching to the right since the foundation of the coalition in 2010 and said there was "increasing divergence" between Lib Dem and Conservative visions for the future. But he rejected any suggestion that the coalition was effectively over, telling Sky News's Murnaghan programme: "I wouldn't say that at all. We have a job to do. It is a job set out in the coalition agreement in 2010 and it is a job we will continue doing right to the election.
"What we also have to do ... is set out the agenda we have for the future of the country. That's where you see an ever-widening gap between the Conservatives and the Liberal Democrats, particularly on the economy and the deficit.
"Both parties agree that we have to finish the job of balancing the books, but the Conservatives set out a plan last week which was all about saying that the working poor should pay the price for dealing with those problems, and they wouldn't be willing to ask the wealthy to pay a single extra penny, whereas we say we've got to finish the job but it's got to be done fairly."
Mr Alexander added: "What we've seen on a lot of issues is the Conservatives move away from the sort of 'compassionate conservatism' they were talking about in 2010 to a much nastier, harder-edged approach. That's a change that's taken place within their party, so you hear more and more about bashing the EU and attacking the Human Rights Act and less and less about fairness.
"We hardly heard the phrase 'We're all in this together' at all at the Tory party conference. You hear nothing at all now about tackling climate change. Over the last few years since we entered the coalition, they've moved more and more to the right in their rhetoric and their policies for the next parliament."
A poll for BBC1's Sunday Politics found that just 27% of Lib Dem candidates for next May's general election regard leader Nick Clegg as an electoral asset, while 45% disagree. Just 36% are happy to use pictures of Mr Clegg on their campaign literature, according to the survey by ComRes.
The ComRes survey found 44% of Lib Dem candidates would prefer a coalition with Labour after the election, compared with 14% who would favour the Conservatives. Some 61% said the Tories had not been a good coalition partner.
Lib Dem president Tim Farron accused the Conservatives of being "borderline immoral" and suggested the Lib Dems would work with the biggest party in the event of a hung parliament.
He told Murnaghan on Sky News: "It's very important that people know a Conservative only government would be lacking in compassion. They are indeed the nasty party that Theresa May said they were. They are trying to balance the books on the backs of the poor, something which is un-British and borderline immoral.
"And the Labour party if they were allowed to govern on their own would be the incompetent rabble they were that got us into this mess in the first place." He added: "What happens after May next year? Well we are going to have to live with it. Whatever the outcome is we will be big enough and grown up enough to work with whoever it is the electorate say we must work with."
Mr Farron claimed the Prime Minister misled the Lib Dems during the coalition negotiations. "Undoubtedly David Cameron pretended to be green, pretended to care about civil liberties, pretended to care about people who are less fortunate than himself and I'm afraid we've been shown none of those things were true."
Schools minister David Laws told BBC1's Sunday Politics the Lib Dems would not oust Mr Clegg if one of the other parties demanded his removal as part of any coalition deal. We are not having some other party tell us who our leader is. Nobody is going to dictate to the Liberal Democrats who leads the party. We will decide that ourselves and we have decided that."
Asked about polling for the programme that showed only one third of Lib Dem candidates were planning to put Mr Clegg on their election leaflets, he said: "From real candidates who are going out now ... we are delighted to put Nick Clegg on our leaflets, we are very proud of what he has done in government."
Lib Dem former foreign minister Jeremy Browne warned that the party would suffer badly at the ballot box if it pitched itself as "half in and half out" of the coalition Government. We have to embrace the opportunity that government has given us, not think like an opposition," he told BBC1's Sunday Politics as he cautioned against overdoing criticism of the Conservatives.
The electorate wanted "more of the same" and the coalition would win easily in many seats if it could stand as one entity at the general election, he said. "Sure, we need to ensure that people understand why we are different from the Conservatives but (not) at the price of looking like we are disowning a coalition which I think is broadly popular in large parts of the country."
Care minister Norman Lamb told Lib Dem activists that Labour leader Ed Miliband was not prime minister material and forming a coalition with Labour could have enormous political implications for the party. Speaking at a fringe event, he said: "I'm afraid I don't see Ed Miliband as a prime minister. I think the idea of us being latched into a Labour government with a low percentage of the vote, led by Ed Miliband, and what's gone on in France under (president Francois) Hollande, I think it could be enormously damaging for our party to be in that sort of relationship.
"It doesn't mean it shouldn't happen if it's the right thing to do for the country. The political implications I think are enormous of that."