Wanted: son of sick boy

It is number one in the HMV T-shirt charts. It is also numbers 2, 3, 4, 5, 8 and 24. Trainspotting T-shirts have joined the paperback and the video as the must-have cultural icon beside every unmade bed. Irvine Welsh's books have become the most stolen titles from one Edinburgh bookshop. Even Glaswegians, genetically sniffy about anything from the east of Scotland, now aspire to Edinburgh. "Radge", "barry", "manto" - some of the more accessible examples of Irvine's vernacular - can now be heard in the style palaces of Sauchiehall Street. It is even socially acceptable, just, to support Hibs.

"Trainspotting certainly stuffed it up the soap dodgers," says Leither Andy Inglis. "Glaswegians think it's hip to be from Leith. Irvine Welsh has given it a bit of a glow, shown it as a place on the edge. He shows that Edinburgh is not just the gentrified capital, a tourist place. It's got a throbbing vitality." Alicia Smith, a Glaswegian living in Edinburgh, has seen her adopted city's cool rating rise. "Suddenly friends from Glasgow want to come here to go clubbing. They even love getting the bus up Leith Walk because it is like being in a scene from the film."

Of course Trainspotting has done more than bring trainloads of Weegies to the Basement bar in search of Irvine necking Becks with his famous and infamous chums. He has created a phenomenon. At the San Francisco book fare last month, a panel discussion on Scottish literature was "mobbed". Welsh wasn't even there - his friend and sometime editor Kevin Williamson, new author Alan Warner and old-timer James Kelman fielded the questions. According to Williamson: "He is an international phenomenon. There were Trainspotting T-shirts everywhere. Everyone had seen the movie. In the City Lights bookshop, there were piles of the book all the way up the stairs."

Phenomenons make profits and publishers and producers on both sides of the Atlantic are frantically searching for The Next Big Thing. The obvious Scottish candidates - young, foul-mouthed, bad skinned - are reeling from the attention. Gordon Legge, a nursing assistant who has published two novels and some short stories, has been on the cover of LA Weekly and interviewed by the New York Times. With one short story Laura J Hird has become "one of the most exciting new writers in Scotland". While in San Francisco, Alan Warner, who is adapting his novel Morvern Callar for the BBC, was taken out for a meaningful drink by the director Robert Altman. Kevin Williamson watched in amazement. "The film was big in the States, Hollywood is definitely interested in more."

Back home, mainstream publishers are at a loss. Literature provides no previous models, punk rock is the most helpful comparison. Just as the Sex Pistols gave other people the idea they could be in a band without being able to play music, Irvine's swaying vernacular suggests, wrongly, that it's possible to be an author without being able to write. And just as A&R men combed the country for bands with the appropriate attitude, publishers are desperate for writers who can appeal to Welsh fans (and they are definitely fans). But the punk model carries a built-in warning. For every Clash there was at least one 999. Kevin Williamson, who runs the Rebel Inc list for Edinburgh publishers Canongate, is ideally placed to mop up any residual talent. His first collection, Children of Albion Rovers, featured Warner, Legge, Hird, James Meek, Paul Reekie and Welsh. Welsh bet Williamson that it would sell out its first print run of 10,000 in the first week. Williamson thought it would sell out, but not so fast. Welsh won.

Albion Rovers is more of a dodgy compilation LP than a sparkling sampler, but so what? Film producers are already sniffing round Welsh's contribution, The Rosewell Incident and the launch party, held in Glasgow, was packed out. "We wanted it to be groovy, with alcohol and music as well as readings," said organiser Ann Donald.

"The phenomenon has got so big that people are rewriting history," says Alicia Smith. "Everyone says they went to Rebel Inc readings in the Unemployed Workers Centre, loved Irvine when he was published by Clocktower Press and read The Shoe (Gordon Legge's first novel) years ago." But it's cool to be cool about it. "There's a guy who works on my ward and he plays in the Edinburgh Eagles 10-pin bowling team," says Legge. He was in the Evening News last week and he brought that in; I brought in my LA Weekly cover. No one was interested in the LA Weekly. They all wanted to look at the Evening News."

London publishers, with their eyes on the bottom line, are less reserved. Industry etiquette makes other firms wary of being seen to do anything as vulgar as cash in, but the race is definitely on to find the next Welsh. Picador admits to describing Dublin writer, Eamonn Sweeney, as "the Irish Irvine Welsh" to their sales reps but blanch at marketing him as such. "We will not slam it out as a paperback original and make it look like Irvine Welsh", said a huffy spokesperson. It's the same story at the Scottish Film Production Fund, says director Eddie Dick, who has noticed an alarming rise in the number of hypodermic syringes in film treatments. "Trainspotting went into development two-and-a-half years ago. Anyone writing a script like that now is two-and-a-half years too late." Robin Robertson, who edits Welsh and Warner at Cape, receives 20 sub-Welsh manuscripts a month. Most are unprintable. Other editors, he says, are looking for the next Irvine Welsh. Not him. "I do hear of others who seem to think they have got to get on this tiresome bandwagon. It takes all the fun out of the process. It is relatively easy to replicate something, so what's the point? The excitement comes from finding something unique. With Irvine, the timing was right and you just can't engineer that again."

The next Irvine Welsh will clearly need to be different from the first. "I don't want to be sitting in New York in two years' time watching Trainspotting 2," says Eddie Dick. "If a fashion is relentlessly pursued it will work itself out quickly and we'll be left saying `now what?' ''

Pressed for a name, Donald gets excited about Graham Lironi's first novel, The Bowels of Christ. Robertson reluctantly namechecks Galway writer Mike McCormack. Legge favours a John Aberdein ("Irvine Welsh with a highland accent, lots of swearing and shagging"). Hird picks poet Brent Hodgson - "Ivor Cutler-esque, ruder and blacker, surreal". Dick mentions an adaptation of Confessions of a Justified Sinner, the novel written by James Hogg in 1824. Williamson just laughs. "No more Irvine Welshes. One is enough."