ED Miliband has been urged to "do a Wilson" and rule out any deal with Nicola Sturgeon as senior Labour sources claimed that most members of the Shadow Cabinet believed the party leader should publicly reject a post-election alliance.

 

Lord Donoughue, former Head of the No 10 Policy Unit under Labour Prime Ministers Harold Wilson and James Callaghan, told The Herald: "It's absolutely essential that the Labour leader comes out as soon as possible, well before the election, against any deal with the Scottish Nationalists. That way, he will make potential SNP supporters realise they can't vote Scottish Nationalist and get a coalition government."

The Labour peer insisted it was unacceptable to have separatists doing deals with a Labour administration as they would seek in various ways to undermine the United Kingdom.

"I was there in 1974 when Harold Wilson ruled out a coalition with the benign Liberals. It is possible to rule out undesirable deals, as Wilson did, and end up as Prime Minister. Ed Miliband should not be afraid of doing a Wilson; after all Harold won four out of five elections."

Lord Donoughue argued that by ruling out a deal the Labour leader would be regarded by the public as acting out of "courage and principle" and added: "It would be entirely to his credit."

The peer claimed several Labour colleagues in the Lords supported this line; Lord Foulkes, the former Scotland Office Minister, has already urged the party leader to reject any tie-up with the SNP.

Another colleague said: "Ed should not do any deal with the Nationalists. He should challenge them to vote him down," noting how this was what happened in 1979 - the anniversary of which falls on March 28 - when SNP MPs voted against the Callaghan government and "heralded in" 13 years of Margaret Thatcher as PM.

At Westminster, there is a growing belief among the party's front and backbenchers that it is a matter of "when not if" the Labour leader will announce he is ruling out any post-poll deal with Ms Sturgeon's party.

One source suggested it is Jim Murphy, the Scottish Labour leader, who is particularly fearful what impact ruling out a deal with the SNP could have on those soft Labour voters, who voted Yes in September's referendum and who might now be torn between voting Labour and supporting the Nationalists on May 7.

Most voters in Scotland, when asked in opinion polls, say their preferred option is a Lab-SNP alliance.

Thus far, the Labour leadership has held the line that the party does not want, is not seeking and will not need any deal with the SNP. Their mantra is vote Labour, get Labour. Yet the opinion polls suggest this is not yet having an impact on Scottish voters.

But many figures in the party are viscerally opposed to having any post-poll arrangement with the Nationalists, whom just months ago they fought tooth and nail against to maintain the Union. Indeed, there are suggestions some might resign their party membership if any deal with the Nationalists were ever done.

"Most of the party wants Ed to rule it out. Most of the Shadow Cabinet, indeed, most MPs want him to rule it out," said a senior insider.

It is suggested Ed Balls, the Shadow Chancellor, and Andy Burnham, the Shadow Health Secretary, are among those particularly keen for their leader to rule out any deal with Ms Sturgeon before the election.

Party sources pointed to growing disquiet south of the border, where candidates in Lab-Con marginals fear that David Cameron and his colleagues, by constantly raising the spectre of a Lab-SNP alliance, will help them lose their contested seats.

"You just have to look at the Tory poster this week(where Mr Miliband is pictured in Alex Salmond's breast pocket) to see how this could hurt us in England," admitted one Labour MP.

Another suggested colleagues were simply ignoring the leadership line on the campaign trail, saying: "Labour MPs on the doorstep are saying: 'If you vote for us we won't do a deal with the SNP.'"