ED Miliband has been urged to rule out any kind of post-election deal with the SNP to stop Labour voters abandoning the party north and south of the border before May 7 as a UKwide poll showed people are two to one against the SNP playing any part in the Westminster government.

After days of the Labour leadership deflecting questions about a possible deal, Ed Balls came closest to, at least, ruling out a full-blown Coalition with the Nationalists.

In a campaign event in London, the Shadow Chancellor accused the Tories of raising a "scare" about a possible Lab-SNP coalition to divert attention from David Cameron's refusal to take part in the leader's debates, declaring such an idea "a complete nonsense argument; we want a majority and that's what we are fighting for".

As the party in Scotland is split between those who want their leader to rule out any deal with the SNP and those who do not, Lord Foulkes, the former Scotland Office Minister, warned that not ruling one out could haemorrhage support for Labour this side of the election.

He declared: "Every Labour MP and peer to whom I've spoken thinks we should rule out any kind of deal with the SNP. What are we waiting for?"

The ex-Minister explained Labour MPs in Scotland were being told by voters they could "vote SNP and still get a Labour government because the Nationalists would support it", ignoring the Labour leadership's plea that every vote for the SNP brings nearer a Tory government.

In England, he explained, party supporters were telling Labour MPs they do not want a deal because one would mean the "SNP would not just be running Scotland but the whole of the UK".

Asked if Mr Miliband should rule out any kind of deal now, Lord Foulkes replied: "Yes. By saying it now, he will influence the outcome."

One English Labour MP admitted not ruling out a deal with the SNP was "damaging" candidates' prospects, noting: "Personally, I would rather we go into a minority government than have to deal with the SNP."

A colleague added: "The Tories are making hay on the SNP issue; not ruling it out could damage us on election day."

Mr Balls, asked to reject a deal completely, said: "The SNP have said they don't want a coalition. It's not part of our plans. We don't want one, we don't need one, we're not after one.

"No large party in the last 100 years - Labour or Conservative - has ever fought a general election on the basis they wanted a coalition or deal with a small party. It's the last thing we want. What we want is a majority Labour government."

The reason the leadership will not rule out a post-poll arrangement with Nicola Sturgeon's party is because Mr Miliband might need the support of the SNP to take power and pass the crucial hurdle of getting through Parliament a Queen's Speech, his programme for government, and avoid a second general election in the autumn.

Meantime, a UKwide poll conducted for Lord Ashcroft, the former Tory treasurer, which gave the Tories a clear lead for the second successive week over Labour - 34 points to 30 - found a large majority of voters saying they do not want the SNP playing a part in a future UK Government with 61 per cent saying they would be unhappy at the prospect of a coalition involving the SNP compared to 31 per cent, who would be happy.

Conservative supporters were opposed by the largest margin, 74 points - 86 per cent to 12 per cent - while Labour voters were also more likely to be unhappy at the prospect, 51 per cent, compared to 44 per cent, who were happy.

Elsewhere, John Mills, Labour's biggest donor, echoed the suggestion from other politicians that it might take a Lab-Con grand coalition to stop the SNP wielding power over the UK.

In the event of no decisive victory, Mr Mills said Labour working with the Tories would be preferable to a deal with the SNP or Ukip.

"If you look at what's happened in Germany and other countries where grand coalitions have happened, they have been reasonably successful," he added.