Sebastian Horsley: Dandy, bohemian and denizen of Soho whose life was his greatest artwork

If Sebastian Horsley hadn't existed it's doubtful anyone would have had the nerve to invent him.

Born into a wealthy but spectacularly dysfunctional family in Hull, a city he later described as a "cemetery with traffic lights", Horsley's life story reads like a fantastic work of fiction. His father Nicholas was an alcoholic socialist who ran a £2bn business selling pork pies to Marks and Spencer's but what he really wanted to be was Allen Ginsberg. His mother Valerie was also an alcoholic who Horsley said "only got out of bed for funerals and to visit the off-licence". The young Sebastian dreamt of being Marc Bolan, and in his teens he attempted to launch a career as a rock singer, but it didn't work out. A failed career as a musician behind him, he headed into the world of art, studying at Central Saint Martins, a school he was expelled from for stealing their equipment.

When his grandfather Alec introduced him to the Glasgow gangster Jimmy Boyle, Sebastian fell under Boyle's spell and he helped him run The Gateway project, which Boyle had set up in Edinburgh to rehabilitate young offenders through art.  

Horsley and Boyle eventually fell out and Horsley returned to London, where he re-launched himself as a dandy, throwing a party at Claridge's for "100 of his closest friends". 

The invites read "Sebastian comes to save London". The event so appalled him that he slunk off early and took a gram of sulphate. While in Scotland alcohol had been his drug of choice – he was once so drunk that he drove his red Rolls Royce to the Iceland supermarket on the Lothian Road and was promptly arrested for shoplifting – he now took up drugs with a passion. He went from being in his own words "a painter who occasionally took drugs to a drug addict who occasionally painted". A period in rehab followed and he cleaned up his act considerably, but never fully gave up his habits saying: "If I had my time again I'd take the same drugs only sooner and more of them".

In 2000, Horsley had himself crucified in the Philippines. It was the event that was, in publicity terms, to define his career. The artist Sarah Lucas filmed the whole thing but unfortunately it had been raining in the run-up to the event, the foot support on the cross collapsed and the structure fell forward on to the screaming villagers. Horsley later quipped that "bad carpentry was the cause, as Jesus the carpenter would have well understood". Many in the press accused him of simply orchestrating a publicity stunt but Horsley retorted that "all art was a publicity stunt" and the motive of all artists was "look at me".

He published his "unauthorised autobiography", Dandy in the Underworld, in 2007, a book that was turned down by its original publishers because they saw it as the work of a disturbed mind. It divided critical opinion every bit as much as Horsley hoped it would. I adapted the book into a stage show which is currently running at the Soho Theatre in London and which Sebastian himself saw the night before his untimely death from a suspected accidental drug overdose.

He was famous for wearing very high top hats and tailcoats on the streets of Soho, but there was ultimately much more to Horsley than simply being a Soho dandy. In print, the man could appear self-regarding but in person Horsley was far from the self-absorbed narcissist he made himself out to be. Many people attest to his kindness, warmth and genuine concern for the welfare of other people. And despite his protestations that of all the sexual perversions monogamy was the most unnatural, Horsley did enjoy a long and happy relationship with the ex-Page Three model Rachel Garley, a woman he never referred to as his girlfriend but as his "muse". It wasn't a monogamous relationship but he remained fiercely loyal to her, and she to him, right until the end. Just weeks before his death she tried to contact him and couldn't. Fearing he had fallen off the wagon and gone back on heroin she rushed round to his Soho studio. When she opened the bedroom door she found him in bed with another woman. She said, "thank God – I thought you were on drugs" and quickly left.

Like his great inspiration, Quentin Crisp, once Horsley put on his dandy costume his character hardened around him, his veneer became his essence and it allowed him to play at life. Just weeks before his death he walked into the Dean Street Townhouse to have dinner with a mutual friend. He couldn't see the friend – he couldn't see much as he was very short-sighted but far too vain to wear glasses – so instead of wandering around the dining room seeking his companion he simply stood in the doorway, pulled out a silk handkerchief and waved it in the air like a Restoration fop. The whole restaurant stopped. Sebastian couldn't see anyone else but he made damned sure they saw him. However, alongside a talent for camp and self-promotion, Horsley was also a Romantic with a capital R. He once admitted to me that he'd spent his whole life placing unrealistic expectations on people and events. He couldn't help self-dramatising and then getting caught up in the fiction he himself had created.

The week the play opened I invited Sebastian to come to see the beautiful set created by the designer Paul Wills in Soho Theatre, yards from his home. It is a re-creation of his Meard Street studio. Sebastian stood in front of it speechless – there was a tear in his eye, and mine. And then he climbed on to the stage and said, "Darling, when can I move in?" Afterwards he emailed Paul and me and said, "I'm sorry I didn't say much. I was just so blown away. It's just so loving". It was almost as if he couldn't believe that was possible.

This week a friend had the grim task of telling his mother what had happened. He said, "I have some bad news: Sebastian's dead." She looked up from her wheelchair and said:"Were his reviews that bad?" Then after making the joke her head fell forward and she whispered quietly, "My poor baby."

Sebastian always described Dandy in the Underworld as a "rock'n'roll book" and his was a rock'n'roll life, and death. It's a cliché to say we shall not see his like again – and the one thing he fought his whole life against was cliché and orthodox thinking – but, it may well be true.

Sebastian Horsley, artist: born Hull 8 August 1962; married 1983 Evelynn Smith (separated; died 2003); died London 17 June 2010.