ALISTAIR Carmichael should “question his whole approach to politics” said Nicola Sturgeon yesterday in a stinging attack on the Scotland Minister.

Carmichael confirmed on Sunday that the inaccurate leaked memo of the First Minister’s conversation with the French Ambassador originated from the Scotland Office, for which he admitted he is ultimately “responsible” as head of the department.

He went on to dismiss the idea that the leak had become a scandal, saying that “in the middle of an election campaign, these things happen”.

But speaking while campaigning in East Dunbartonshire, Sturgeon said: “I think Alistair Carmichael really needs to question his whole approach to politics if he thinks dirty tricks and smear campaigns are just how things are done in elections.

“I take a very different view. I think elections should be a battle of positive ideas and that’s how I’ll continue to campaign.”

She said: “I didn’t say what I was alleged to have said. The French Ambassador has said I didn’t say it, so that part of this story really has been dealt with and should no longer be an issue.”

The memo leaked on Saturday night was written by a British civil servant and contains information about a conversation between the First Minister and the French Ambassador in which it was claimed Sturgeon expressed a preference for seeing David Cameron in Number 10.

The allegations were both strongly denied by both the First Minister and the French Ambassador and an inquiry into the leak, headed by Sir Jeremy Heywood, is being held.

Sturgeon said that the questions should now be “who wrote this memo, how did it come to contain such an inaccuracy, but most importantly of all how did it very conveniently fall into the hands of the Daily Telegraph?”

The First Minister said: “I appreciate the SNP’s challenging the Westminster establishment in this election. We’re challenging the old boys’ network and we’re challenging that cosy consensus of Labour, the Liberals and the Tories who want more austerity cuts. So, I guess it’s not surprising there are people in the Westminster establishment who don’t like that message and who want to fight back against it, but I’ll continue to take our positive message to the doorsteps, the streets, the communities of Scotland, because I believe it’s the right one,” she said.

Deputy SNP leader Stewart Hosie further dismissed the idea that the SNP are hoping for a Conservative government saying he “could see” Ed Miliband as leader because he leads the Labour Party.

Hosie said: “We are an anti-Tory party, we are an anti-austerity party. We have offered Ed Miliband a deal. We would not prefer to see a Tory government. The damage Tory governments do to ordinary people is so bad.

“Of course one could see him as prime minister. He is leader of the Labour Party and therefore quite conceivably could be. Of course I could see him as prime minister.”

A YouGov poll published yesterday said the SNP are on track to win 46 per cent of Scottish votes, which could land them 47 seats.

Labour is on 29 per cent, with YouGov predicting the party losing as many as 30 seats.

The survey also revealed very worrying statistics for Scotland’s Liberal Democrats, suggesting just three per cent of the Scottish electorate will vote for them this year, down from 19 per cent in 2010.

If the figures remain constant up to the General Election on May 7, the LibDems could retain only one of their 11 Scottish MPs, with both Carmichael and Danny Alexander, the Chief Secretary to the Treasury under the Coalition, facing a struggle to stem the rising tide of SNP support.