The diary of a nobody

William Boyd understands the art of a good hoax and the hoax of good art. Sitting in the drawing room of his Chelsea house, we are surrounded by walls patchworked by canvases.

But I'm here to discuss the creator of a group of drawings that line Boyd's hallway, and represent one of the great cultural pranks of the 20th century. The sequence of small paintings signed "Nat Tate" are from the artist's 1950s White Buildings series, in which skeletal outlines of American houses flicker beneath semi-translucent whitewashed oils.

In the spring of 1998, Boyd wrote a short biography of Tate, which has been out of print for years but which Bloomsbury is now reissuing in hardback, owing to popular demand. "It's kind of a fable," says Boyd. Over 60 short pages, we learn how the New Yorker Tate was a gifted Abstract Expressionist, a sparring partner to Jackson Pollock, an alcoholic, and a troubled orphan who tried to destroy all his work. Echoing the death of the US poet Hart Crane, he threw himself off the Staten Island ferry in 1960 at the tender age of 31.

However, what the monograph Nat Tate: An American Artist 1928-1960 does not reveal, is that Tate is a total fiction.

In 1998, Boyd was on the editorial board of the periodical Modern Painters, whose editor asked him how fiction could fit into the magazine. "So I said, 'Why don't I invent a painter?' And then Bowie said 'Let's bring it out as a little book', because he had a publishing company. So the thing just grew and grew." ("Bowie" is David Bowie. Also in the high-profile conspiratorial gang were Gore Vidal and Picasso's biographer, John Richardson.)

Boyd was busy plotting Any Human Heart at the time, so he employed its hapless hero, Logan Mountstuart, as a contemporary witness to Tate's fate. He added shading and perspective to the hoax with photographs and quotations, all fraudulent layers of verisimilitude. And then there are illustrations of Nat's works, as realistic as period Willem de Koonings.

The conceit took on a life of its own, first appearing in Modern Painters, then extracted in the The Telegraph, and finally published with a celebrity launch – on April Fool's Day – in Jeff Koons's Manhattan studios. The great and the good lapped it up. "People love a hoax. There's something atavistic about it, particularly if the people being hoaxed are a little bit pleased with themselves," explains Boyd. "So a lot of black-clad glitterati or literati in Manhattan going around saying, 'I think I own a Nat Tate' just added to it."

Nat Tate, Any Human Heart and Boyd's fake autobiography, The New Confessions, attempt to push fiction into the bounds of the real. "My plan was to publish Nat deadpan, say nothing about it and then just see what happened, see when it detonated," says Boyd. It was David Lister, the arts editor of The Independent, who sparked the charge. He overheard incriminating comments between two of "the inner ring of conspirators". It clearly rankles, not least as they brought Lister into the circle of trust only for him to publish an exposé before a launch in London. The resulting scandal made the front page of The New York Times and landed Boyd in front of Jeremy Paxman on Newsnight.

Nat Tate includes a pastiche of a Frank O'Hara poem, circa 1957, detailing the Greenwich Village scene: "We were lucky people, lucky to be living then and in NYC. Quelle chance! Lucky (watch out posterity, here we come!) that we had such great names." It signals Boyd's love of quirky monikers.

"I think you should make every character's name memorable in a way. If you call someone Philip Norton it's not very interesting but if you call them Christian House it has a ring to it." Although flattered, I'm aware that my name doesn't rank up there with the roll call of Boyd's intriguing major and minor players. From Any Human Heart's Land Fothergill to Armadillo's Lorimer Black, a name is never just a name. "I'm in the last days of my new novel, and my head is full of the names of my characters," says Boyd. "It starts in Vienna in 1913 and ends in 1915, and Edwardian names are really weird. The head of MI6 was called Mansfield Cumming, for example. Did his family call him Manny, or what?"

The novel, Waiting for Sunrise, teems with such diverse types as Freud, Wittgenstein, Klimt, Schiele, and a deranged vagrant named Adolf Hiter. Boyd considers himself a literary time traveller. "You try and think what must it have been like to be Kokoschka having an affair with Alma Mahler. In 1913 they were at it like nothing on earth," laughs Boyd. "You realise how the world was quite modern. For example, you could buy a pre-paid book of sixpenny telegrams, you had 12 words and you could write your telegram, pop it in a postbox and somebody would get it two or three hours later. Like a text!"

Does Boyd see his characters as friends? "I always quote Vladimir Nabokov, who was asked that question. He said, 'No, all my characters are galley slaves and I'm the man on the deck with the whip.' Tish! Back to work,'" Boyd lashes out his hand and chuckles.

The irony is that to some extent Boyd is self-flagellating. Those intricate, ethereal works in the hallway were created by his hand. He is Nat Tate. "There's a frustration, because I wanted to be a painter when I was 17. I wanted to go to art school but parental hands said no, you shall not go," says Boyd with measured regret. "It was a real love and passion, but the forking path led me in the direction of the novel."

Nat Tate: An American Artist 1928-1960, By William Boyd, Bloomsbury £15

'... It was a charged, exciting time, and for Nat Tate a first real taste of escape, of true independence. Like everybody else, like every other artist he met, Nat began drinking heavily, joining the long, long bender that was going on around him. Gore Vidal met him at this time and remembered him as an "essentially dignified drunk".'