ED Miliband has attempted to quash weeks of Tory jibes that he will try to "crawl" into Downing Street with SNP backing by ruling out a formal coalition with the nationalists.

The Labour leader insisted there will be no power-sharing deal with Nicola Sturgeon's party and he would not lead a government that included SNP ministers.

"It will not happen," he said at a town hall-style campaign event in Guiseley.

"There are big differences between us ...

"Labour will not go into coalition government with the SNP.

"There will be no SNP ministers in any government I lead."

The intervention followed growing concerns about the damage being inflicted by repeated refusals to rule out a coalition.

Labour figures had previously dismissed speculation over a post-election deal as "nonsense". But with polls suggesting the SNP could win dozens of seats north of the border, they had stopped short of an unequivocal commitment.

At Prime Minister's Questions last week, David Cameron lambasted Mr Miliband as "weak and despicable" for considering a deal with "people who want to break up our country".

Mr Miliband made clear today there would be no coalition with the SNP - a prospect Ms Sturgeon had already described as "unlikely" - but indicated he would not be drawn on any looser arrangements that could arise after May 7.

"I'm not going to spend the next eight weeks speculating about what might or might not happen after the polls have closed," he said.

"It is vital we spend the next eight weeks debating the real choice facing the British people in this election: a choice between a better future for Britain with a Labour government or the failing plan of this Conservative government.

"Our campaign is 100 per cent focused on winning that debate to win the Labour majority government that can bring the change Britain needs.

"Now the Tories, the party that haven't won a majority for over 20 years, are now running a misleading campaign based on the idea of a Labour-SNP coalition... this idea is nonsense."

Responding to M Miliband’s comments on a deal with the SNP, a Conservative Party spokesman said: "This changes nothing.

"Ed Miliband will not rule out a deal with the SNP because he knows it's impossible to become Prime Minister without being carried into Downing Street in Alex Salmond's pocket.

"There have been over 1,200 votes in this Parliament. Vote by vote, bill by bill, issue by issue, Ed Miliband would have to do a deal with the SNP on each and every one of them.

"Who knows what Ed Miliband will sell out to Alex Salmond on: more borrowing, more debt, higher taxes or weaker defences. But one thing's for certain: it's hardworking taxpayers who will pay the price for this chaos."