Charles Saatchi and Nigella Lawson argued over two former personal assistants accused of misappropriating £170,000 moments before he was photographed with his hands around her neck, reports have claimed.
Mr Saatchi, 70, is suing the women after they allegedly spent tens of thousands of pounds on designer products, taxi journeys and a flight to New York.
But Ms Lawson, 53, is understood to be close to the women – who were employed to look after her children from her first marriage – and did not want her husband to take them to court.
Friends say the women were a factor behind their row at an exclusive restaurant in Mayfair that resulted in Mr Saatchi accepting a caution for assault.
News of the impending court battle came as Ms Lawson was spotted house-hunting on Friday. She reportedly viewed an £11,000-a-month rental home in a central London mews.
Italian sisters, Francesca, 34, and Elisabetta 'Lisa' Grillo, 32, are alleged to have misappropriated money to buy luxury goods including a £3,616 Virgin Atlantic flight to New York and items from Prada, Miu Miu and Chanel.
Francesca was paid £28,000 a year, while Elisabetta was paid £25,000 to carry out childcare duties as well as activities related to Mr Saatchi's business interests.
Both began working for Ms Lawson when she was married to her first husband John Diamond, who later died of cancer aged 47 in 2001.
They are due to appear before Isleworth Crown Court later this year.
A source told the Mail on Sunday: "The Grillo girls had been very close to Nigella for a long time.
"She brought them into the marriage and she has naturally been very defensive about all this. I don’t think she particularly wanted them to be sued. That’s one of the things they were rowing about over the now infamous lunch.
"Charles was criticising her for allowing the assistants free rein and things clearly got a bit heated. One of them was allegedly spending money on Chanel handbags and other designer stuff. He thinks Nigella has been too easy on them."
Mr Saatchi initially described the incident as a “playful tiff”, claiming that he had held Miss Lawson’s neck repeatedly to “emphasise my point” while the couple discussed their children.
However, Mr Saatchi later voluntarily went to Charing Cross police station and accepted a caution for assault. He explained that he did this to avoid having the incident “hanging over all of us for months”.
Miss Lawson moved out of the marital home in Chelsea, West London, over a week ago and is temporarily staying in a rented apartment in an exclusive private members’ club in Mayfair.
She has since been seen in public without her wedding ring, but has so far made no comment about the incident.
Richard Cannon of Janes Solicitors, who is acting for the Grillo sisters, said in a statement. "Our clients will continue to vigorously defend themselves both in the civil proceedings before the High Court and the criminal proceedings before the Crown Court."