Nigella Lawson has admitted in court she used cocaine on two occasions but insists she is not a habitual user of the drug.
The celebrity chef (53) made the remark when questioned as she gave evidence at Isleworth Crown Court in London, at the trial of two former personal assistants accused of spending thousands of pounds on company credit cards.
She said "I have been put on trial here where I am called to answer, and glad to answer the allegations, and the world's press, and it comes after a long summer of bullying and abuse. He (Saatchi) had said to me if I didn't get back to him and clear his name he would destroy me".
Following a much-publicised incident at Scott's restaurant in London, where her ex-husband was pictured with his hand on her throat, false allegations of drug abuse about her began circulating on a "PR blog" she said.
She added these allegations were "dedicated to salvaging Mr. Saatchi's reputation and destroying mine".
The court heard she had been reluctant to give evidence at the trial and said Mr. Saatchi made the comment in reaction to that reluctance. Ms. Lawson told the court that Mr. Saatchi had a temper, "didn't like to take part in family life", and shouted and swore at her.
"She broke our heart"
It is alleged that between January 1st 2008 and December 31st 2012 Italian sisters Elisabetta and Francesca Grillo committed fraud by abusing their positions while working for the couple.
The jury was told they are accused of using credit cards loaned to them by the TV chef and art dealer to spend more than stg£685,000 on themselves.
Prosecutors claim the women lived the "high life", spending the money on designer clothes and handbags from Louis Vuitton, Christian Dior and Vivienne Westwood.
Ms. Lawson told the court: "It's very difficult when you find out that someone you have loved and trusted could behave that way. In my heart of hearts I do not believe Lisa (Elisabetta) to be a bad person. I believe her not to have a very strong moral compass. She broke our heart".
She added that she once took out stg£7,000 from her savings to pay for Elisabetta Grillo to have her teeth fixed.
Elisabetta (41), sometimes referred to in court as Lisa, and co-defendant Francesca (35) both of Kensington Gardens Square, Bayswater, west London, deny the charge against them.
