Scotland’s former First Minister Nicola Sturgeon has described her arrest by police investigating the SNP’s finances as the worst day of her life.

Sturgeon describes being questioned by detectives as part of Operation Branchform in an extract from her upcoming memoir which has been published in The Times.

Sturgeon also writes about her “utter disbelief” about police raiding the home she shared with her husband Peter Murrell in April 2023.

Elsewhere in the extracts, the former SNP leader describes the pain of suffering a miscarriage and sets out her views on sexuality, which she says she does not consider “to be binary”.

Sturgeon writes that she was in bed when her husband answered the door to police officers around 07:00 on 5 April 2023.

“It was with a sense of utter disbelief that I realised the police were in my home, that they had a warrant to arrest my husband and search the house,” she writes.

“I was in despair, struggling to comprehend what had happened.”

Sturgeon was arrested in June 2023. She was told in March this year that she would face no further action and was no longer a suspect.

Her husband, the former SNP chief executive Peter Murrell, was charged with embezzlement in April 2024.

The couple announced they were separating earlier this year.

Sturgeon said that during period between the raid on their home in April 2023 and her arrest she felt like she “had fallen into the plot of a dystopian novel.”

When she was arrested, she was: “Horrified and devastated, though also relieved in a strange sort of way. At least the ordeal of waiting was over.

“Sunday, June 11, was the worst day of my life. Being arrested and questioned by the police is an experience I’m not sure I will ever get over.

“When I eventually left the police station, late that afternoon, I was in a bad state mentally. I went to a friend’s house in the northeast of Scotland and stayed for a week.”

She said the day when she was informed that no action would be taken against her, a day on which Mr Murrell appeared again in court, was “a day of deeply mixed emotions.”

“The feeling of relief, and release, was overwhelming,” she writes.

Sturgeon also talks in detail about her experience of becoming pregnant and suffering a miscarriage aged 40 in 2010.

She said she had never yearned for a baby but her husband desperately wanted to be a dad.

When she found out she was pregnant, she writes, “Peter was ecstatic. I wanted to be. I told him I was. But — and I still feel so guilty about this — I was deeply conflicted.

“In my stupid, work-obsessed mind the timing couldn’t have been worse. By the Scottish election, I would be six months pregnant. It may seem hard to believe now, but even in 2010 it wasn’t obvious how voters would react to a heavily pregnant candidate,” she writes.

Sturgeon writes about the guilt she felt at being conflicted about the pregnancy and the guilt she now feels after miscarrying.

“Later, what I would feel most guilty about were the days I had wished I wasn’t pregnant. There’s still a part of me that sees what happened as my punishment for that,” she writes.

She also describes continuing to work while suffering “constant agony, the most excruciating pain I have ever experienced” and feeling “heartbroken” about the loss.

Sturgeon says that she was convinced the baby would have been a girl called Isla, writing: “I do deeply regret not getting the chance to be Isla’s mum.

“It might not make sense, but she feels real to me. And I know that I will mourn her for the rest of my life.”

The former first minister also addresses rumours about her sexuality, in particular an unfounded claim that she was having an affair with a female French diplomat.

“There were slightly different versions of the story, but the consistent theme seemed to be that I was having a torrid lesbian affair,” she writes.

“In one of the variants of the story, there had been a violent encounter between us, involving an iron, in Edinburgh’s Balmoral Hotel. We had also supposedly set up a love nest, in a house in Bridge of Allan, that I had bought from Andy Murray’s mum, Judy.”

Sturgeon writes that she would normally have ignored such “wild stories from the darker recesses of social media,” but this one ended up being discussed by her neighbours, family and friends.

She describes much of the social media and online comment as being driven by homophobia.

“For many of those peddling it, “lesbian” and “gay” are meant as insults. However, while the fact I was being lied about got under my skin, the nature of the insult itself was water off a duck’s back,” she writes.

“Long-term relationships with men have accounted for more than thirty years of my life, but I have never considered sexuality, my own included, to be binary. Moreover, sexual relationships should be private matters.”

Frankly will be published on Thursday 14 August.