Who is Peter Murrell, the former SNP chief executive?

But now Ms Sturgeon, who became both SNP leader and Scottish First Minister in 2014, is quitting those roles, while the contest to replace her has divided the party and seen her husband dramatically resign.

Mr Murrell, 58, who had been party chief executive since 1999, was the man responsible for the day-to-day running of the SNP, which was at one point the second largest party in the UK.

That job meant Mr Murrell was one of the most influential figures in Scottish politics, despite having never been an elected politician or a figure much in front of the cameras.

READ MORE: Peter Murrell resigns as SNP chief executive with immediate effect

However, yesterday he announced he was resigning with immediate effect amid a row over the party's membership numbers and transparency.

It comes almost a quarter of a century after he succeeded Michael Russell, the current SNP president, as the party's chief executive, who is now taking on his work on a voluntary basis until a permanent successor has been recruited.

Before that Mr Murrell had worked in the constituency office of former SNP leader and First Minister Alex Salmond.

Mr Murrell married Ms Sturgeon, then SNP depute leader and deputy first minister, in 2010, with Mr Salmond, the then first minister, among the guests.

Mr Murrell is regarded by many as having played a key role in transforming the party's fortunes, helping to modernise SNP operations.

While membership has fallen from the peak of about 125,000 achieved in 2018, to the recently revealed total of 72,186, the party remains the largest and most dominant political force in Scotland.

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And with Mr Murrell and Ms Sturgeon at the helm, the SNP has cemented its electoral dominance, having been in power at Holyrood since 2007 and won every election north of the border since then.

However, critics of the SNP under Ms Sturgeon's leadership, both inside and outside the party, have long questioned whether it is appropriate to have the key roles of leader and chief executive held by one couple.

Hearings at Holyrood in late 2020 and early 2021 into the handling of harassment allegations made against Mr Salmond saw Mr Murrell's role came under further scrutiny.

At one point he was accused of giving contradictory evidence to the committee investigating the Scottish Government's botched handling of harassment allegations against Mr Salmond.

Nicola Sturgeon and her then fiance Peter Murrell at their home in 2010.  Photo Nick Ponty/The Herald.

The inquiry was set up after Mr Salmond won a judicial review against the Scottish Government over its handling of two sexual harassment complaints. The Court of Session ruled that the investigation was unfair and tainted by apparent bias. It awarded him £512,250 in legal costs.  Mr Salmond was later acquitted of separate criminal charges after a trial at the High Court in Edinburgh.

During his evidence to the committee Mr Salmond claimed there was a plot against him which included Mr Murrell, SNP chief operating officer Susan Ruddick, SNP compliance officer Ian McCann, and Ms Sturgeon’s chief of staff, Liz Lloyd.

He cited text messages sent by Mr Murrell which were later obtained by Kenny MacAskill, a former SNP justice secretary who is now an MP in Mr Salmond's Alba Party.

One text from Mr Murrell, on 25 January 2020, said it was a “good time to be pressurising” police as they were “twiddling their thumbs” during an apparent lull in their investigation.

READ MORE: SNP calls on race to continue in 'positive spirit' as Russell steps in

A second said: “The more fronts [Salmond] is having to firefight on the better for all complainers. So [Crown Prosecution Service] action would be a good thing.”

Mr Salmond claimed they had been motivated by the judicial review, which they regarded as calamitous for Ms Sturgeon, and alleged they went on a fishing exercise for police complaints to give impetus to a criminal investigation that started in late 2018.

He said the goal had been to have the police investigation “overtake” the judicial review, allowing the Scottish Government to have it paused, or “sisted”, or to eclipse the loss of the judicial review with his trial.

Mr Murrell rejected Salmond’s claims the texts proved a conspiracy but, in his evidence session acknowledged the language was inappropriate and “out of character.” He said: “To me, that suggests just how upset I was at the time.” During her evidence to the committee Ms Sturgeon said the plot claim was “bizarre”.

In their final report MSPs rejected Mr Salmond’s allegations of unaccepted interference in the police investigation and collusion.

Separately, questions have been asked about the whereabouts of £600,000 which was donated to the SNP for independence campaigning, with Police Scotland confirming last year it was investigating.

Mr Murrell meanwhile loaned the party £107,620 in June 2021 to help with cash flow in the wake of the most recent Scottish Parliament elections with reports last year suggesting about half of this cash had been repaid by October 2021.