Nicola Sturgeon has said she has faith in everything the police investigating the SNP’s finances are doing, despite some of her supporters alleging heavy-handed tactics.

The former First Minister also said people shouldn’t worry about the state of her marriage after both she and husband Peter Murrell were arrested as part of the probe.

In her first sit-down interview since she was quizzed by detectives and released without charge, Ms Sturgeon said she was “absolutely certain she had done nothing wrong”. 

However she refused to speak on behalf of Mr Murrell or anyone else in the case, and dodged questions about the infamous £110,000 motorhome acquired by her party.

The ex-SNP leader was speaking to broadcaster Iain Dale’s All Talk show on the Edinburgh Fringe at the Pleasance EICC.

Police Scotland has been investigating whether £660,000 raised by the SNP specifically for Indyref2 was misspent for the past two years under Operation Branchform.

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On April 5, a few days after Humza Yousaf replaced Ms Sturgeon as FM, officers arrested Mr Murrell, the former SNP chief executive, and searched the couple’s Glasgow home.

They also raided the SNP’s Edinburgh HQ and seized a luxury campervan from outside the home of Mr Murrell’s widowed 92-year-old mother in Dunfermline.

A fortnight later, SNP treasurer Colin Beattie was arrested and Ms Sturgeon’s arrest followed in June. All three were released without charge.

Ms Sturgeon insisted she had “no idea” that the raids were coming when she announced her resignation as SNP leader and FM in mid-February.

She also said she “wouldn’t have been able to function” in the weeks afterwards, before the handover to Mr Yousaf, had known what lay ahead.

Asked about the day her husband was arrested, she said the first she knew was when police knocked at her door.

Put to her that the police operation that day, with a blue evidence tent on her lawn, had been “over the top”, Ms Sturgeon said: “It’s obviously been a very difficult, traumatic experience. People live through worse. I’m not going to overstate that.

“My touchstone, I guess, in all of it all along, is that I’m confident in my own position.

“I’m absolutely certain that I’ve done nothing wrong.

“Therefore I need to, and do, trust in the process. 

“The police are doing a job, and therefore I have to have faith that everything they’re doing in the process of that is justified, and I’m going to continue to have faith in that.

“The touchstone is the confidence in my own position.”

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She said she had found “depths of resilience” she didn’t know she had, even after leading the country during the pandemic, and learned “the importance of friendship”.

She said: "There’s a group of people, my closest friends, that have been utterly indispensable to me in the last few months.

“I probably wouldn’t have the emotional wherewithal to sit here right now but for them.

“It’s not an experience I would have chosen, but even out of the toughest things, I’m finding you learn things about yourself and you learn things about life.”

Asked what was going through her head when her husband was being quizzed in the police station, she said: “I have no idea. I was with my mum and dad.

"Always go back to your mammy and your daddy when things get… I can’t remember everything that was going through my head at that point, it was not the best day of my life, put it that way.”

Asked if she realised it was inevitable she would be questioned as well, Ms Sturgeon said she thought it was “more likely than not” but realised she was not in control of events.

“There’s no point trying to second guess it.”

Asked if she was confident that her husband was innocent, she refused to say, saying she could only speak for herself on such a serious matter.

Asked if she talked to her husband about it, she said: “Put it this way, I think I’m choosing when I can to talk about happier things.”

Mr Dale asked: “What effect has it had on your marriage?”

Ms Sturgeon replied: “My marriage is not something anybody should worry about.”

Asked when she first knew of the £110,000 motorhome bought by the SNP, Ms Sturgeon said: “These are questions that go to the heart of things that the police are looking at.

“I’m not going to get into it.”

Asked when she last visited her mother-in-law, and so would have seen the vehicle, Ms Sturgeon again chose not to give a straight answer.

She said: “My mother-in-law has just been admitted to a care home. 

“I haven’t visited my mother-in-law as often perhaps as I should have done over the last couple of years because of Covid, my work, her work.

“So, you know, maybe that’s something that doesn’t reflect particularly well on me.”