Opening the trial, prosecutor Jane Carpenter said allegations of drug abuse by the TV chef were not central to the trial of Francesca and Elisabetta Grillo, who each deny a count of fraud.
“This case is a case about fraud, you may be aware of matters which have been in the press concerning Mr Saatchi and specifically an incident outside a restaurant in June and allegations of drug taking by Mr Saatchi about Ms Lawson more recently.
“We say it’s fraud motivated by greed and that’s what this trial is about. Not about other issues of matrimonial discord or drug taking.
“This trial, the prosecution say, relates to the high life lived by Francesca and Elisabetta Grillo.
“The sort of life you may often see portrayed in glossy magazines. But we say that they did so not by their own endeavours but in a greedy and fraudulent free-for-all by abusing the trust of their employers in a four-year spending spree.”
Mr Saatchi has alleged that Ms Lawson had taken cocaine regularly for years.
Ms Carpenter said the sisters were “employed to ensure the smooth running of Ms Lawson and Mr Saatchi’s household”, with duties that included looking after their children, even sometimes going on holiday alone with the youngsters.
They lived rent-free, with Elisabetta, aged 41, paid £25,000 a year, and Francesca, aged 35, paid £28,000 annually.
Ms Lawson, who employed the sisters before her marriage to Mr Saatchi, “acknowledged that they were extremely close to her family”, Ms Carpenter said.
Both were given credit cards to buy items for the household and family members with the balance paid off each month by direct debit without being closely scrutinised and an understanding that they would not use it for themselves.
Ms Carpenter told Isleworth Crown Court in west London this was often the arrangement for staff.
“For some people, however, the temptation of having a card that they can use with impunity to buy high-value goods is too great.
“It must be a dishonest employee’s dream to have a company credit card that’s always accepted.”
Among the luxury goods the sisters bought were items from Louis Vuitton, Chanel, Miu Miu, and Prada, the court heard.
“They travelled the world, staying in top hotels, and spent exorbitant sums of money on designer clothes and accessories.
“By the time their fraud came to light they had incurred expenditure which was in excess of £685,000.
“Despite the defendants’ silence, it’s anticipated that they will claim that Mr Saatchi and Ms Lawson permitted them to use the credit cards to buy themselves presents and withdraw cash because of the long hours they worked.
“The defendants’ case is that Ms Lawson’s alleged drug use and the defendants’ knowledge of it materially affected Ms Lawson’s attitude to the defendants’ spending.
“An intimate atmosphere was created by such knowledge, which affected their relationship. Their case is that this expenditure was expressly or implicitly consented to by Ms Lawson. The Crown say that, although Mr Saatchi and Ms Lawson were generous employers who treated the sisters very well, it’s preposterous that they would authorise such levels of expenditure to personal assistants.”
The court heard that Francesca Grillo spent the most money on the credit card, which was registered to Conarco Partnership, one of Mr Saatchi’s companies.
She was estimated to have used it to buy goods for herself worth over £580,000 while her older sister’s total spend was estimated to be around £105,000.
The court heard that the alleged offences came to light in June last year after Mr Saatchi’s finance director Rahul Gajjar noticed the high level of spending.
Both women admitted they had been using the cards for personal expenditure, jurors heard.
The trial was adjourned to 10am today with Mr Saatchi due to give evidence.