Tom Gordon

Scottish Political Editor

DISGRACED former Scottish Secretary Alistair Carmichael is facing a House of Commons ethics probe into the leak of a misleading memo about Nicola Sturgeon.

It is understood several members of the public yesterday asked the Parliamentary Commission for Standards to investigate whether Carmichael broke the MPs' Code of Conduct by leaking the memo to damage Sturgeon and the SNP in the election campaign.

Section 16 of the Code says MPs "shall never undertake any action which would cause significant damage to the reputation and integrity of the House of Commons as a whole, or of its Members generally".

Any MP who breaches the code and is suspended by the Commons for 10 sitting days then faces a by-election if 10 per cent of their constituents sign a recall petition.

Carmichael, 49, has faced growing pressure to stand down as the LibDem MP for Orkney and Shetland since admitting his part in the so-called "Frenchgate" affair on Friday

A Cabinet Office inquiry found he and his former special adviser Euan Roddin arranged the leaking of a Scotland Office memo to the Daily Telegraph which said Sturgeon wanted David Cameron to stay in power and didn't think Ed Miliband was Prime Minister material.

The claims, based on an account of a meeting between Sturgeon and Sylvie Bermann, the French Ambassador to the UK, would have been hugely damaging to Sturgeon given her stated opposition to Cameron and her plan to help a Miliband-led Labour government.

However it quickly emerged that the claims, although recorded in good faith by a Scotland Office civil servant, were inaccurate, and a leak inquiry was launched.

After phone records proved Roddin contacted the Telegraph on April 1, two days before the story appeared, Carmichael admitted he had personally sanctioned the leak, despite subsequently denying any knowledge of it.

On Friday he apologised to Sturgeon for his "error of judgment" - she questioned whether he could stay an MP given his "blatant election dirty trick".

Two online petitions calling for Carmichael to quit had last night attracted 15,000 backers.

However the LibDems appear intent on weathering the storm rather than losing their last MP in Scotland and trying to defend a 817-vote majority in a by-election.

The party said it would not discipline Carmichael and remained supportive of him.

Former LibDem leader Sir Menzies Campbell added: "Alistair Carmichael has made a mistake. He has apologised for it. And that should be an end of the matter."

Dismissing the idea of a by-election, Carmichael's Labour and Conservative opponents in the election also claimed the SNP were hyping the issue for their own ends.

However SNP deputy leader Stewart Hosie told Radio 4 that Carmichael should consider quitting because he went into the election telling voters he was not involved in the leak.

"He ought to consider very seriously whether he can be even be trusted by his constituents to remain a Member of Parliament. I hope this is investigated fully and thoroughly."

Although Carmichael stopped being an MP on March 30, the memo was written on March 6, and the SNP believe Carmichael may have discussed leaking it while still he was still subject to the MPs Code of Conduct.

The SNP also called on Scottish LibDem leader Willie Rennie, who commented within hours of the story breaking, to say if he had discussed the leak with Carmichael.

It also emerged last night that two LibDem MSPs, Tavish Scott in Shetland and Liam McArthur in Orkney, proposed and seconded Carmichael as the LibDem candidate and signed his election papers.

Scott refused to comment, while McArthur could not be contacted.

But Councillor Theo Smith, former chair of the Shetland LibDems and another of Carmichael's election signatories, told the Sunday Herald: "I'm very disappointed".

Hugh Halcro-Johnston, vice chair of the Orkney LibDems and former convener of Orkney Islands Council, said he was "unhappy about the involvement of civil servants in what was basically an electoral ploy" and admitted that Carmichael's reputation had taken a "dent", but said he remained an excellent local MP.

"It would be an absolute tragedy if our last Liberal Democrat MP in Scotland was to lose his seat through something like this."