Dame Mary Archer has given evidence as a defence witness at the trial of one of her “closest friends” Lady Lavinia Nourse, who is accused of historical sexual abuse.

Lady Lavinia, the widow of Court of Appeal judge Sir Martin Nourse, told police that the allegations against her were “Cloud Cuckooland”, jurors heard on Thursday.

Sir Martin died in 2017 aged 85.

His 77-year-old widow is on trial at Peterborough’s Nightingale court, in the Knight’s Chamber at the city’s cathedral, where she denies 17 counts of sexually abusing a boy under the age of 12.

Defence barrister Jonathan Caplan QC introduced Dame Mary to jurors as the wife of Lord Jeffrey Archer, chairman of the Science Museum and President of Addenbrooke’s Charitable Trust in Cambridge.

Dame Mary said that she first met Lady Lavinia in 1980 when they were both living in Grantchester, near Cambridge, and Lady Lavinia asked if she would open her garden to the public as part of a scheme she was helping with.

Dame Mary told jurors she and the defendant were also “both completely cat mad”.

Asked to describe Lady Lavinia’s character, she said: “Kind-hearted, generous.

“If I say house proud that’s not what I mean to say, but her two houses that I knew were always beautifully done.”

She said she recalled a time “in the early 80s when she didn’t seem so well”, adding that she did not know the reason for this.

“I leapt to the conclusion that she must have had a miscarriage or something,” she said.

She added that Lady Lavinia was “one of my closest friends and one of my oldest friends too”.

Lady Lavinia, of Newmarket in Suffolk, was voluntarily interviewed about allegations of historical sexual abuse at Parkside police station in Cambridge in January 2019 with a solicitor present, the court heard.

A transcript of part of her interview under police caution was read to the jury, with Detective Constable Mark Beaven reading his lines and Lady Lavinia’s responses read by prosecution barrister Jennifer Knight QC.

In the interview transcript, Mr Beaven asked Lady Lavinia: “What account could you give me about that allegation?”

She replied: “It simply never happened.”

She told the officer: “I had depression, mental breakdown, I suffer from quite severe depression.”

Mr Beaven asked if this “incapacitated” her, to which she replied: “Yes, I was receiving therapy.”

She told the detective she was “pretty shocked” when she heard about the boy’s allegations.

“To me this is a complete fantasy,” she said.

“I don’t know what he’s talking about.”

Later in the interview, she said: “I’m finding this very difficult.

“It really is Cloud Cuckooland.”

Lady Lavinia denies all charges, which relate to the same male complainant and are five counts of indecently assaulting a boy and 12 counts of indecency with a child.