* Accuses ex-husband of threatening to destroy her
* Says she took cocaine with dying first husband
* Personal assistants accused of lavish spending (Adds details)
By Alexander Winning
LONDON, Dec 4 (Reuters) - Celebrity cook Nigella Lawson told a court she had taken cocaine several times including when being subjected to "intimate terrorism" by her millionaire ex-husband Charles Saatchi, in the latest dramatic twist in a trial that has gripped Britain.
A well-known TV star and author in Britain and the United States, Lawson also told the court on Wednesday she had smoked cannabis occasionally in the final year of her marriage to art dealer Saatchi but had "never been a drug addict or abuser".
"I don't have a drug problem, I have a life problem," said Lawson, nicknamed the "Domestic Goddess" after the title of one of her best-selling recipe books.
The 53-year-old was testifying at the trial of two of her personal assistants who are facing fraud charges relating to the alleged misuse of 685,000 pounds ($1.12 million) on a credit card belonging to Saatchi's company.
Last week the assistants' defence counsel said there was a tacit understanding they could spend what they liked as long as they did not tell anyone about Lawson's drug use. They deny the fraud charges. The court has also heard Saatchi wrote Lawson an email in which he accused her of being "off her head" on drugs.
Lawson said on Wednesday she had taken cocaine on six occasions with her first husband, journalist John Diamond, as he was dying of throat cancer in 2001.
"It was a small amount but it gave him some escape," said the cook, who is due to feature as a mentor and judge in U.S TV cooking competition show "The Taste" in the new year, on Walt Disney Co's ABC network.
She said she also used the drug in July 2010. "I was having a very, very difficult time," Lawson said. "I felt subjected to intimate terrorism by Mr Saatchi," she said.
"I would say with some shame that I (also) smoked the odd joint in the last year of my marriage (to Saatchi). I am now totally drug-free," she added.
Lawson and Saatchi, 70, ended their 10-year marriage in July, and he accepted a police caution after newspapers published pictures of him with his hands around his ex-wife's neck at a London restaurant a month earlier.
The fraud case has exposed the bitter rows between them, once one of Britain's most famous couples. Interest in the case has also been stoked by the extent to which the assistants allegedly treated themselves to lavish purchases on the credit card and the drug allegations levelled at Lawson.
Flanked by police officers, Lawson arrived at at Isleworth Crown Court in west London on Wednesday to a barrage of flashlights and TV arc lights from jostling media crews from around the world.
Earlier in court, she accused Saatchi of threatening to destroy her with false drug allegations. She said she had been reluctant to give evidence because of such allegations, which she said followed "a long summer of bullying" from Saatchi.
"I felt this would not become a fraud case and I would be put on trial and that is what happened," she said. "But I'm glad to answer the allegations here and to the world's press," she added.
Lawson told the jury that following the "awful incident" at the restaurant in June, false allegations of her drug use began circulating on what she called a PR blog.
Those allegations, she said, had been "dedicated to salvaging Mr Saatchi's reputation and destroying mine".
She told the court her reluctance to give evidence in the trial had angered Saatchi. "He had said to me if I didn't get back to him and clear his name, he would destroy me," she added.
The court had previously heard that Saatchi wrote her an email in October in which he said the two assistants on trial, Italian sisters Elisabetta and Francesca Grillo, would be able to beat the fraud charge because of her drug use.
"I can only laugh at your sorry depravity," he said in the email, which was read in court. "Of course now the Grillos will get off on the basis that you ... were so off your head on drugs that you allowed the sisters to spend whatever they liked."
In court last week, however, Saatchi said he had no proof that his ex-wife had ever taken drugs. "Are you asking me whether I think that Nigella truly was off her head? Not for a second," he said.
The court has been told by the prosecution that in the four months to June 2012 alone, Francesca Grillo, 35, spent an average of 48,000 pounds per month and 41-year-old Elisabetta 28,000 pounds.
At various times during the four years to which the charges relate, the court has heard, the sisters spent lavishly on flights to New York, hotel stays, designer handbags and clothes.
Lawson told the court Elisabetta was a stalwart who had helped her through the death of Diamond. She said the fraud allegations "broke our heart" when revealed to her and Saatchi.
The trial continues. (Writing by Stephen Addison; Editing by Pravin Char)