Quiet Mosley boy thrust into spotlight by father’s sex case

Considering who his father is and his grandfather was, Alexander had stayed largely under the radar, writing academic papers on economic and mathematical theorems.

It is deeply ironic that in death at the age of just 39 from a suspected drugs overdose, Alexander should finally create his own headlines.

Last year, he had been dragged into the bizarre court case brought by his father Max Mosley against the News of the World, in which the motor racing boss had admitted indulging in perverse sexual practices.

There is no evidence that the confessions had affected Alexander, although at the privacy trial his father had told the High Court: "It [News of the World] had more of an effect on my family than it did on me. My wife... never knew of this aspect of my life, so that headline in the newspaper was completely, totally devastating for her.

"Also, for my two sons, I don't think there is anything worse for a son than to see in a newspaper, particularly one like the News of the World, pictures of the kind they printed. I can think of nothing more undignified or humiliating than that. If I put myself in their position — to see my father in that position — I would find it devastating."

Educated at Westminster School, alongside the likes of writer Giles Coren and chef Tom Pemberton, Alexander was best known as something of a maths genius.

He went on to study maths at Oxford University before obtaining a PhD in a maths and economics-related field at the University of London. He appears to have avoided politics or even a public profile.

His grandfather was the notorious fascist Sir Oswald Mosley, founder of the British Union of Fascists, who was interned during the Second World War along with his socialite wife Diana Mitford.

Max Mosley, born in 1940, and his brother Alexander, were spared internment.

Alexander — known to friends as Al — is said to have had a drugs problem, living alone in his £1 million house in Notting Hill. But he had also forged a successful business career, joining up with his old friend Pemberton to launch the successful and critically-acclaimed Notting Hill restaurant Hereford Road.

It had been Alexander's brainchild. He was the money man who identified the site for the restaurant. Alexander did the books; Tom did the cooking. Alexander had first tried to persuade his friend in 2005, opening in 2007.

Alexander is also listed as a director of Marine Current Turbines Ltd. The business describes itself as "the world leader and first mover in marine current and tidal stream energy".

The only glimpse into his private life is on social networking website Facebook, although the profile was removed this afternoon. His friends included members of the aristocratic Guinness family, to whom he was related. He was a member of just one group on Facebook — its title? "Max Mosley is ruining F1".