ALISTAIR Carmichael, the former Scottish Secretary, is to be investigated by Westminster's sleaze watchdog into whether or not he broke the MPs' code of conduct over the leaking of the memo designed to smear Nicola Sturgeon during the General Election campaign.
The office of Kathryn Hudson, the parliamentary commissioner for standards, confirmed she would be looking into the matter, even though at the time of the leak to the Conservative-supporting Daily Telegraph Mr Carmichael was not an MP as the Westminster Parliament had been dissolved.
A spokeswoman for Ms Hudson declined to comment on this point, saying: "The commissioner has to establish the facts." 
It is possible the former Cabinet Minister knew of the leak while still an MP.
The investigation has been sparked by a complaint. Asked who had made it, the spokeswoman declined to say as complaints are made in confidence. However, once Ms Hudson releases her report, expected to be by the end of the year, then the complainant's name together with all correspondence will be published.
If it is concluded that Mr Carmichael was in serious breach of the code of conduct, then the commissioner will pass her report to the House of Commons Standards Committee, whose sanctions range from seeking an apology to suspension. 
If the latter were to be more than 10 sitting days, then under the Recall of MPs Act, this would spark a by-election if, within six weeks, 10 per cent of the electorate signed a recall petition; on Orkney and Shetland, this would be around 3,000 people. 
Mr Carmichael hit the headlines last month when it was revealed that he had personally approved the leaking of the memo to the Telegraph by his special advisor. 
The memo was an account of a private conversation between the First Minister and Sylvie Bermann, the French Ambassador, in which, it was wrongly claimed that Ms Sturgeon had said she wanted David Cameron to remain Prime Minister and Ed Miliband was not up to the job. This was in direct contradiction to her public utterances in which she said she wanted to "lock out" Mr Cameron from No 10 and put Mr Miliband in.
As soon as the leaked memo was published, Ms Sturgeon insisted it was "100 per cent untrue". The French Embassy also said it was inaccurate. 
A subsequent Whitehall inquiry concluded a Scotland Office civil servant had written the memo, believing it to be an accurate account of the Sturgeon/Bermann conversation but later accepting part of the conversation could have been "lost in translation".
Mr Carmichael accepted full responsibility when the inquiry report emerged following the election, admitting that if it had been published while he had still been a Minister, he would have resigned.
The commissioner's office said her investigation would be focused on certain parts of the code, including ones that covered: the need to "avoid conflict between personal interest and the public interest"; that confidential information received by an MP in the course of their parliamentary duties should only be used in pursuit of them and that MPs should not act in a way that would "cause significant damage" to the integrity of the Commons.
Mr Carmichael was unavailable for comment but a Liberal Democrat spokesman said: "Alistair has always been clear that he would co-operate with any investigation that was undertaken; that remains the case. He will co-operate in full with the standards commissioner's investigation."
The SNP's Pete Wishart welcomed Ms Hudson's investigation, saying it underlined the seriousness of the allegation against Mr Carmichael. 
"The people of Orkney and Shetland need an MP, who is fully focused on representing them and the needs of the constituency," he added.
Last week, four petitioners, including at least one SNP member, lodged a petition at the Court of Session in Edinburgh, seeking the quashing of the MP's election victory; his majority was reduced from more than 10,000 to just 817. 
Campaigners were able to raise more than £43,000 in an online fundraising drive. 
The petition alleges the former Scottish Secretary breached Section 106 of the 1983 Representation of the People Act, which outlaws false statements in relation to the "personal character or conduct" of a candidate.