Ecclestone Stunt
Formlula 1 boss Bernie Ecclestone (L) and his son-in-law James Stunt Reuters / IBTimes UK composite

It is a divorce case that is more fitting for a Guy Ritchie movie than London's Central Family Court.

With blacked-out Rolls Royces, billions of pounds worth of assets and eccentric characters making threats to kill, James Stunt and Petra Ecclestone's break up has all the drama and turbulence required to fill the director's next feature-length project.

The pair are fighting over assets worth £5.5bn ($7.2bn) in what may be Britain's biggest divorce battle.

Now, after years of keeping quiet about his son-in-law, Formlula 1 boss Bernie Ecclestone has blown the lid about the failed love affair and his strained relationship with Stunt.

In an interview with the Mail on Sunday, the 86-year-old tycoon revealed a series of troubling incidents which included an alleged threat to put a bullet in Petra's head.

"He was going to blow her head off, he threatened her with something," Ecclestone said.

"He was going to threaten her. It wasn't very nice and that's why she went to the police.

"He was being a bit abusive and a little bit silly. [But] when you say something, you've probably been thinking along those lines or else you wouldn't say it."

The alleged threat is said to have taken place at the luxurious restaurant The Rib Room inside five-star Jumeriah Carlton Tower hotel in London's Belgravia and police have since confirmed that Stunt was arrested as a result of the flare-up.

Petra was said to have been so frightened by Stunt's fit of rage that she scurried off and hid inside the cupboard of their £68m ($89.6m) mansion in Chelsea and made frantic calls to her mother and older sister.

Ecclestone said he believes Stunt's "abusive and violent" nature comes from his affinity of gangsters, who he believes the 35-year-old is trying to emulate.

"He's impressed with those sort of people," Ecclestone said. "I think he watches all those gangster films and had big respect for them."

"People have said to me, 'He thinks he's John Gotti.'"

One photo taken of Stunt since his initial divorce hearing last Wednesday – where he is said to have made a shooting gesture at Ecclestone and called him a "c**t" – shows him seated in the back of a Rolls Royce, puffing on a cigarette and clutching two porcelain cats.

So consumed with his own gangster personality, Stunt confessed he is scared of potential assassins and could always be seen carrying around an Evian water bottle filled with his own home-made juice out of fear of being poisoned.

Ecclestone said he wished Petra had spoken to him about the extent of her problems, but revealed that he may have unleashed his own gangster-like side on Stunt if she had.

"She's very private, like I am," he said. "She doesn't go round explaining her problems. If she's got problems, she keeps them to herself and deals with them on her own. It's a great shame that she didn't speak to me earlier."

He added: "If she ever had come to me and said he'd done something, it wouldn't be good for him."