Tiffs between Formula One drivers, usually over dangerous on-track behaviour, are no rarity — but few can have the bitterness that has split Lewis Hamilton and Adrian Sutil.

They competed against each other in Formula Three in their formative race years and were once best friends. Not any more.

And, ironically, their ongoing spat has nothing to do with any antics by either man in the heat of a grand prix. It was triggered when Sutil crazily overstepped the mark and wounded Eric Lux, then chief executive of Renault F1, by thrusting a champagne glass into his neck in a nightclub fracas after the China GP in 2011.

The German’s astonishing assault earned him an 18-month suspended jail sentence and a fine of €200,000 (Dh957,179) and lost him his Force India seat. And, crucially, it put the brake on his F1 dreams after a five-year spell.

He has now been given a career lifeline by Force India as partner to Paul di Resta — but his fall-out with Hamilton is ongoing. It happened because Hamilton, celebrating his win in China that night, had refused to stand as a witness at Sutil’s trial.

And Sutil, who felt betrayed by his long-term friend’s lack of support, called him “a coward”.

They were both on duty at pre-season rehearsals in Spain last week and Sutil revealed: “I am not in contact with him any more. I’ve not seen him. I’ve not spoken to him.

“So we have no relationship at the moment. For sure we will meet up, but I don’t know what will happen.”

Hamilton, for his part, claims to have made an effort to resume his friendship and says: “As soon as I found out he had got his drive back at Force India I sent him a message congratulating him.

“I had said a prayer for him that I really hoped he would get the seat because he deserves it. But I’ve heard nothing from him.”

Sutil’s setbacks don’t end with a broken friendship. Despite his confidence it won’t happen, he could be refused entry to some countries staging a grand prix because of his criminal record for violence.