Nicola Sturgeon and her closest aides are facing months of gruelling scrutiny over the botched Alex Salmond sexual misconduct probe after a second inquiry was confirmed into the affair.

Amid venomous fighting between Ms Sturgeon and Mr Salmond’s camps, Holyrood confirmed a special committee of MSPs would examine the case.

The role of Ms Sturgeon and her chief of staff, Liz Lloyd, is to be pored over after revelations about their behaviour while Mr Salmond was under investigation.

The latest inquiry threatens to hamstring Ms Sturgeon and her inner circle just when they had hoped to be talking about the chaos over Brexit and the merits of independence.

Mr Salmond and Ms Sturgeon said they would be happy to cooperate with it.

Illustrating the bitterness of the SNP feuding, Ms Sturgeon’s official spokesman said Ms Lloyd was the subject of a “vendetta” by Mr Salmond’s allies, who he described as “the other side”.

Mr Sturgeon said on Monday that she was the victim of a “smear” campaign.

The Holyrood inquiry is in addition to Ms Sturgeon’s asking ethics watchdogs to check if she broke the ministerial code by having secret minutes and phone calls with Mr Salmond last spring and summer.

Interim Scottish Tory leader Jackson Carlaw compared Ms Sturgeon to the former US President Richard Nixon, who resigned amid a political scandal.

The comment led to jokes at Holyrood about the White House’s ‘Tricky Dicky’ and Bute House’s ‘Tricky Nicky’.

Mr Salmond won a judicial review against the Scottish Government last week, forcing it to admit that it had bungled its investigation of two sexual misconduct complaints against him.

The complaints, lodged in January 2018 but referring to 2013, were checked by an official who had already been in contact with his accusers, tainting the process.

After the probe collapsed and left taxpayers with a £500,000 bill, Ms Sturgeon admitted she had three meeting and two calls with the former First Minister during the investigation, but insisted she did not interfere in it.

She said she first learned of the probe when Mr Salmond told her himself on April 2 at a meeting at her Glasgow home, and that she met him in her capacity as SNP leader, not as First Minister, despite the subject being a “government process”.

The meeting was not minuted and Ms Sturgeon only reported it to the government’s top official, Permanent Secretary Leslie Evans, two months later.

It emerged yesterday that Mr Salmond took a lawyer with him to Ms Sturgeon’s home, undermining Ms Sturgeon’s claim that it was a simple SNP matter.

Mr Salmond was accompanied by Duncan Hamilton, the advocate who later acted as junior counsel in his judicial review case.

Ms Sturgeon last week withheld Mr Hamilton’s name, merely telling MSPs that “Mr Salmond was represented” - her office then repeatedly refused to name who was involved. 

Mr Hamilton’s presence was revealed by Mr Salmond’s former chief of staff, Geoff Aberdein, who said Ms Lloyd told him before the meeting, in late March, that she suspected that a misconduct complaint had been levelled against Mr Salmond, but she did not know any specifics, and had not told Ms Sturgeon.

When the conversation was relayed to Mr Salmond it was interpreted as an attempt by Ms Lloyd to put him off trying to return to frontline politics, adding to his tensions with Ms Sturgeon.

Ms Aberdein said he was also at Ms Sturgeon’s home on April 2, but that Ms Sturgeon and Mr Salmond talked alone.

Mr Carlaw said it stretched credulity that Ms Lloyd had discussed a complaint against Mr Salmond with Mr Aberdein, then arranged a meeting between Mr Salmond and the First Minister without telling her what was coming.

He said: “If it’s true, the chief of staff was failing in her duty, and if it’s not true, the First Minister was even more reckless in proceeding with the discussion.”

Ms Sturgeon’s spokesman declined to elaborate on Mr Aberdein’s statement or Ms Lloyd’s role,  maintained April 2 was a “party” meeting, and said Ms Sturgeon continued to have full confidence in Ms Lloyd and Ms Evans.

A spokesperson for Mr Salmond said: “Alex will be happy to co-operate, in principle and if asked, with a parliamentary inquiry which seeks to examine how the administration of the Scottish government could get itself into a position where the Court of Session had to rule that it had acted unlawfully, unfairly and tainted by apparent bias.

Welcoming the Holyrood inquiry, Scottish Labour leader Richard Leonard said: “This is the right decision and a positive step forward. Full transparency in this matter is essential in order for the public to have confidence in the First Minister and the Scottish government.”