OPPOSITION politicians have called for a probe into whether Nicola Sturgeon broke the ministerial code to be expanded following explosive claims made by Alex Salmond.

MSPs from the Liberal Democrats, Conservatives and Labour have written to Deputy First Minister John Swinney asking him to formally widen the remit of the investigation.

It comes after Mr Salmond accused Ms Sturgeon of misleading the Holyrood inquiry into her government's treatment of him, calling her evidence “simply untrue” and "untenable".

READ MORE: Sturgeon 'looks forward to addressing absolute nonsense around Salmond affair'

He said she had also misled parliament and thus broken the Scottish ministerial code, which if correct would be regarded at Holyrood as a resignation matter.

Mr Salmond said he was prepared to repeat his claims, which have so far been made in writing and shared with the Holyrood inquiry, in person under oath. 

A Holyrood inquiry is looking into how the Scottish Government botched its probe into sexual misconduct allegations made against Mr Salmond in 2018.

The former first minister had the exercise set aside in a judicial review after the Governmend conceded it was flawed and “tainted by apparent bias”, an error that left taxpayers with a £512,000 bill for his legal costs.

He was later cleared of multiple charges of sexual assault at the High Court in Edinburgh.

Mr Salmond has now submitted evidence to James Hamilton QC, the independent adviser on the Scottish ministerial code, and this has been shared with MSPs on the Holyrood inquiry committee.

Mr Hamilton, a former Irish prosecutor, is investigating whether Ms Sturgeon broke the ministerial code.

READ MORE: Alex Salmond accuses Nicola Sturgeon of giving 'untrue' evidence to Holyrood inquiry

MSPs want Mr Swinney to formally widen the remit of this probe to include claims by Mr Salmond that the First Minister misled parliament over when she knew of sexual misconduct claims against him.

Mr Salmond has also called for the investigation to be widened.

Ms Sturgeon initially told Holyrood she first heard of complaints of sexual misconduct against her predecessor when they met at her home on April 2 2018.

It later emerged she had an informal meeting with Mr Salmond's chief of staff, Geoff Aberdein, in her Holyrood office four days earlier.

The SNP leader said she "forgot" about the encounter.

A spokesman for Ms Sturgeon said she denies Mr Salmond's claims and stands by her previous comments on the issue.

Now four members of the Holyrood inquiry - Labour's Jackie Baillie, Liberal Democrat Alex Cole-Hamilton and Conservatives Margaret Mitchell and Murdo Fraser - have written to Mr Swinney calling for him to formally extend the remit of the independent inquiry into whether or not the First Minister breached the ministerial code.

They have also written to Mr Hamilton asking him to clarify if the inquiry will be expanded as requested.

READ MORE: Ian Blackford says Nicola Sturgeon ‘acted honourably’ as Alex Salmond claims she breached code

Both letters state: "If corroborated, Mr Salmond's evidence could prove that the First Minister knowingly misled Parliament both orally and in writing on several occasions about when she first knew that the government was investigating complaints against the former first minister and of her actions around the same.

"Equally, Mr Salmond may be fabricating his assertions in an effort to damage Ms Sturgeon. 

"In any case these two versions of events cannot both be true and we believe it to be of paramount importance to the national interest that the facts of the matter are established."

The letters say widening the investigation to include examination of whether Ms Sturgeon broke the section of the code dealing with knowingly misleading parliament is "vital".

The MSPs tell Mr Swinney: "When asked previously, both yourself and the First Minister have repeatedly suggested that James Hamilton QC is at liberty to expand the remit of his inquiry should the evidence require it.

"However, we understand that as he engaged in a quasi-judicial process, he cannot indulge in mission creep and that the remit may only be formally expanded by an official directive from your government."

Mr Swinney told the BBC's Politics Scotland programme on Sunday: "I answered a parliamentary question in November which made clear the James Hamilton inquiry on the ministerial code could look at any aspect of a potential breach of the ministerial code.

"So what is being demanded by Alex Salmond and the Scottish Conservatives was put in place by me in a parliamentary answer in November, so I have absolutely no idea why on earth they are going on about it today."

He said Ms Sturgeon is looking forward to putting to rest "some of the absolute nonsense that has been circulating" about the Alex Salmond affair.

The full letter to John Swinney:

Dear Deputy First Minister 

Formal request to expand the current Ministerial Code investigation of Nicola Sturgeon MSP, to include possible breaches of Section 1 (c). 

We are writing to you as a cross party group of MSPs, informed by our work as members of the committee of inquiry into the Scottish Government Handling of Harassment Complaints. We ask that you formally expand the remit of the current investigation into whether Nicola Sturgeon breached the ministerial code under the terms of Section 1(c) in relation to the harassment complaints against Alex Salmond, the government’s handling of the same and her statements to parliament on this matter. 

Under the terms of the self-referral by Nicola Sturgeon, James Hamilton QC is currently limited to ascertaining whether the First Minister failed to feed back the basic facts of several meetings and discussions held with Alex Salmond to her private office as required by sections 4.22 and 4.23 of the code and furthermore whether she sought to influence the government handling of the complaints against him in any way.  

Following sight of the account of the former first minister published on Friday and in light of other material available to our committee, we believe it is now vital that Mr Hamilton’s investigation be expanded to include consideration of another potential breach, by the First Minister, this time of Section 1 (c) of the Ministerial code: 

“Section 1 (c) It is of paramount importance that ministers give accurate and truthful information to the parliament, correcting any inadvertent error at the earliest opportunity. Ministers who knowingly mislead the parliament will be expected to offer their resignation to the First Minister;” 

Mr Salmond’s submission raises many questions, some are beyond the scope of our inquiry, but they are clearly at odds with the account of events offered to parliament by the First Minister. If corroborated, Mr Salmond’s evidence could prove that the First Minister knowingly misled parliament both orally and in writing on several occasions about when she first knew that your government was investigating complaints against the former First Minister and of her actions around the same. Equally, Mr Salmond may be fabricating his assertions in an effort to damage Ms Sturgeon. In any case these two versions of events cannot both be true and we believe it to be of paramount importance to the national interest that the facts of the matter are established. 

When asked previously, both yourself and the First Minister have repeatedly suggested that James Hamilton QC is at liberty to expand the remit of his inquiry should the evidence require it. However, we understand that as he engaged in a quasi-judicial process, he cannot indulge in mission creep and that the remit may only be formally expanded by an official directive from your government. 

Please consider this a formal request for you to widen the remit of Mr Hamilton’s investigation with such a directive. 

We look forward to your response. 

Alex Cole-Hamilton MSP, Margaret Mitchell MSP, Jackie Baillie MSP, Murdo Fraser MSP.