Ms Pasternak claims the US writer’s 2019 bestseller The Secrets We Kept borrows heavily from her 2016 book, Lara: The Untold Love Story and the Inspiration for Doctor Zhivago. Ms Prescott told the judge that publishing her novel was the “realisation of a lifelong dream” but that the court case turned the success of her award-winning bestseller into a nightmare.

In her book, Ms Pasternak sets out her theory that Olga Ivinskaya, her great uncle’s wife, was the real-life inspiration behind Lara Antipova, the central character in the much-loved novel by Boris Pasternak.

But in the High Court, Ms Prescott accused her rival of having “copied and pasted” sections of earlier books about her relative for her own work, which Ms Prescott’s lawyers say contains a “staggering” amount of “copying.”

She said: “I knew I was named after Lara, the character in the movie.”

“As a girl, my mother had loved David Lean’s film adaptation of Doctor Zhivago, as well as the book it was based on. As a child, I’d wind up her musical jewellery box again and again to hear it play Lara’s Theme and watch the tiny ballerina inside slowly spin.”

She added: “Today, I’m working on a second novel while being a first-time mother to a toddler during a pandemic. These allegations and this claim have been highly stressful.”

“Publishing The Secrets We Kept was the fulfilment of a lifelong dream and I’ve been very proud of it. Still, at times, I wish I hadn’t written it.”

“Not because Anna Pasternak is right, but because the book and its success put me in her crosshairs. I felt such anger and sadness upon receiving these claims and threats.”

“I always thought a Pasternak might take issue with my depiction of Boris. I never thought one would accuse me of copying.”

Ms Prescott admits she read Ms Pasternak’s book and included it in the acknowledgements in her novel.

But she says she was already two years into the process of writing before she saw her rival’s book and denies its influence was “substantial.”

Instead, she claims that both she and Ms Pasternak relied on the same historical source material, including Olga Ivinskaya’s memoirs A Captive of Time, and The Pasternak Affair by Sergio D’Angelo.

Dr Zhivago is Boris Pasternak’s most famous work and the subject of David Lean’s 1965 blockbuster, in which Lara is played by Julie Christie with Omar Sharif in the title role.

The novel follows the love story of Yuri Zhivago and Lara Antipova during the Russian Revolution and First World War.

The hearing continues.