George Osborne today repeatedly refused to rule out a power-sharing deal with Ukip, as Nigel Farage his price for propping up the Tories.

The Chancellor challenged Labour to reject a coalition with the SNP, but side-stepped questions about whether the Conservatives would rely on Ukip to form a government.

It came as Mr Farage said he would be willing to support a Tory minority government only if a referendum on Britain leaving the EU was held before the end of this year, two years earlier than David Cameron plans.

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Chancellor George Osborne challenged Labour to reject a coalition with the SNP, but side-stepped questions about whether the Conservatives would rely on Ukip to form a government

Last month Tory party chairman Grant Shapps explicitly ruled out a coalition with Ukip, vowing: 'We are not going to do pacts and deals with Ukip.'

But Mr Cameron has refused to make the same commitment, telling MailOnline: 'I don't want to have a coalition with anybody.

'I'm fighting for a majority government, there are 93 days to go and I'm not going to speculate about any outcome other than victory.'

Today Mr Osborne demanded that Labour say it would not form a coalition with the SNP, who are expected to make big gains in Scotland.

But he refused to make the same promise about a Tory-Ukip tie-up. Appearing on BBC One's Andrew Marr show, Mr Osborne said: 'It's just total nonsense, voting for Nigel Farage makes Ed Miliband the likely Prime Minister and it means instead of getting the referendum on Europe we get no referendum at all, so that's what a vote for Ukip is about and it's a fundamentally different situation from the SNP, you were asking Ed Balls about it, he again refused to rule out a deal with the SNP.

'We are fighting for a majority, we only need 23 more seats to get that majority.

'Nigel Farage and indeed Ed Balls are trying to muddy the waters, it's a fundamentally different situation for this reason - Nigel Farage is not going to win seats in the House of Commons, even on his own boasts he's only going to win a small handful.

'The SNP are likely to win dozens of seats because of the collapse of the Labour party, Ed Miliband can't be Prime Minister without the support of Alex Salmond and that creates an alliance between those who want to bankrupt the country and those who want to break up the country.'

Mr Farage has claimed that his party will win more than 10 seats on May 7, which means the Tories would likely also need the support of Northern Ireland's Democratic Unionist Party (DUP) to maintain a minority government.

Ukip would back the Tories' first budget if a referendum on Britain's EU membership was promised before the end of 2015.

Nigel Farage is willing to do a deal with the Conservatives after the election on the condition that an EU referendum is held before Christmas

Up until now, the Prime Minister has vowed to hold a referendum by the end of 2017, and has said he will campaign to stay in a reformed EU.

But the latest polls suggest neither the Conservatives or Labour will have enough seats to form a government, meaning Mr Cameron may have to find a compromise.

In an extract from his memoir, published in the Sunday Telegraph, Mr Farage said: 'Depending on how many seats Ukip gets, I could see the Tories, Ukip and the Democratic Unionist Party doing some kind of deal.

'The terms of my deal with the Tories would be very precise and simple. I want a full and fair referendum to be held in 2015 to allow Britain to vote on being in or out of the European Union

'There would be no wiggle room for 're-negotiation' somewhere down the line.'

The Ukip leader added that he did not want a formal coalition with the 'ghastly' Conservatives and that he would not sit in a future Cabinet with the Prime Minister.

In his The Purple Revolution book, Mr Farage set out four criteria for the proposed referendum, which the Prime Minister would have to agree with.

Up until now, Prime Minister David Cameron has vowed to hold a referendum on Britain's membership of the EU by the end of 2017

The points to thrash out include the timing of the vote, the wording of the question, who would be allowed to vote and media coverage.

The Ukip leader also said that a referendum could be organised within weeks, rather than waiting two years for a 2017 vote.

Under his plans, EU nationals living in the UK with foreign passports would not be eligible to vote - meaning his German wife Kristen would not be allowed to take part in the ballot.

If Mr Cameron agreed with his terms, 'there is no question that Ukip would not do a deal', Mr Farage said.

The DUP is also in favour of a referendum on the EU and is currently the largest party in Northern Ireland with eight MPs in the House of Commons.

Mr Farage added that Labour would not win the election because it has lost support in Scotland and the north of England.

Douglas Alexander, Labour's Shadow Foreign Secretary, said: 'David Cameron has already changed his position three times on Europe in the face of internal pressure from his backbenchers and external pressure from UKIP.

'Now we know that Nigel Farage is demanding further new concessions in return for helping the Conservatives cling on to power.

'Nigel Farage wants a Tory government. UKIP is ready to prop up a Tory government and support their plan to take spending levels back to the 1930's when we didn't have a health service. The question is whether Cameron will cave in and take even more risks with our membership of Europe and Britain's economy.