14/08/2014 16:51 BST | Updated 22/05/2015 10:12 BST

Did Jealousy Of Nigella Lawson's Son Bruno Spark Charles Saatchi's Attack?

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Nigella Lawson has emerged from her silence since leaving the marital home she shared with Charles Saatchi by publishing a Twitter picture of a homemade chocolate birthday cake for her son Bruno's 17th birthday.

It's thought that her public display of motherly love may have a deeper meaning as it emerged that the shocking scenes of the TV chef being held by her neck by her husband Charles Saatchi at Scotts restaurant in Mayfair on 15 June were linked to ongoing disputes between the couple over Bruno.

A friend has told the Sunday Express: "It was because of Bruno. Charles doesn't want him living in their house any more.

"He says he feels 'crowded' – even though their house is huge.

"Nigella is naturally protective. She's not about to just see her son chucked out but whenever the subject is broached it always ends in an argument. Charles is as stubborn as a mule.

"The crux of the dispute between Charles and Nigella has been over Bruno. Charles has never really got on with him and is now, in his bizarre macho way, flexing his muscles over his territory - he wants Bruno out. Nigella thinks he's being terribly unkind and mean."

Bruno and his older sister Cosima, 19, are Nigella's children by her first husband journalist John Diamond, who died of throat cancer in 2001. Bruno was four at the time of his father's death.

When Nigella, 53, moved out of the £14 million home in Chelsea with Bruno, her husband Charles Saatchi played down photographs of him grabbing her by the throat and tweaking her nose

Saatchi, 70, accepted a police caution for assault for the shocking scenes that provoked their split, despite describing it as a 'playful tiff'.

The advertising tycoon turned modern art mogul was photographed grabbing Miss Lawson by the throat and tweaking her nose during a 27-minute long horrifying scene.

But Nigella appears to have dashed any hopes that the couple can be reconciled. She has been living with her son at an apartment above Little House members' club while she decides on their future. She has not worn her wedding ring since the argument.

On Friday Nigella was spotted looking pale and wan and being shown around a central London mews house accompanied by her sister Horatia and children Cosima and Bruno. Cosima is thought to be on a gap year abroad but has returned to support her mother.

Meanwhile removal men have emptied the marital home of box after box of possessions, including cooking pans, guitars and skateboards.