American graphic novelist Neil Gaiman, writer of the Sandman comics, has written an unsettling new book- a horror story for children - but questions about moving on from the world of comics to 'serious' work annoy him, he tells Donald Clarke

'I remember being taken down to the cellar where they were all waiting for us," Neil Gaiman says, his voice dropping to an ominous rumble. "Each boy would go in for about 15 minutes and then the next would go in. So, after two hours waiting, I went in and he said, 'An interesting set of test results, Neil. What do you want to do?'

"I said, 'I want to write American comics.' Well, he looked at me as if I'd just waved a kipper at him. He stared at me for a bit - a pause that went on for an uncomfortably long time - and said, 'Have you ever thought about accountancy?' "

The theatrical manner in which Gaiman tells the story of his teenage encounter with sinister career advisers is characteristic of the man and his work. He doesn't quite begin each answer with "It was a dark and stormy night", but the Hampshire-born author of the unsettling new children's book Coraline makes no attempt to contain his storytelling instincts. Those instincts have held him in good stead. Giving two fingers to the men in the cellar, Gaiman left school, played around with journalism for a while and then joined talents like Alan Moore and Belfast's Garth Ennis in forwarding the pocket revolution that brought comics to the brink of respectability in the late 1980s and early 1990s.

"That movement makes more sense in retrospect," Gaiman says. "All those things need a genius and ours was Alan Moore [London-based author of wildly imaginative graphic novels such as Watchmen and From Hell]. He really was sui generis. He could have done anything, but chose this medium because he loved it.

"In America, comics were the landscape - they were everywhere. But over here, American comics were like postcards from Oz. They had fire hydrants, pizza parlours and sky scrapers in them. For us fire hydrants and sky scrapers were every bit as strange as super-heroes flying through the air. For us that world remained strange. They'd go into our brains in the same place that, say, a Dennis Potter play would go in."

Gaiman made his name with the epic fantasy the Sandman. Beginning in 1988, the monthly comic ran for another eight years and is now published in 10 dense, vividly illustrated compendiums. The titular protagonist is the personification of the human dream world - a sad-eyed eternal around whom Gaiman spins expansive, but neatly structured, tales.

"I met somebody recently who is doing a PhD on it," he says. "They all seem to think that I set out to write a classic work in 10 volumes. I have to explain that there were no graphic novels when I started out. Old comics went straight into the bargain bin."

But, as time progressed, Gaiman began to realise that the Sandman was gathering a more permanent following: "It started out that our audience was 16-year-old boys. Then we acquired a substantial female readership. That hadn't happened before. Then the 40-year-olds began turning up at signings. But I really knew it was getting serious when people began arriving with Sandman tattoos. On one occasion, this guy got me to sign his arm beneath his tattoo. He came back after the signing and he had my signature tattooed on his arm: there was still liquid skin and blood attached to it. And then I thought: now this is different!"

He shudders. But with his leather jacket bulging full of pens and his shaggy black hair falling over his eyes, the 41-year-old author still seems very much of that world. And he makes no attempt to distance himself from the comic fraternity. Nonetheless, in recent years, he has increasingly devoted his time to film, TV and fiction. Do the publication of 2001's chunky novel American Gods and the well-reviewed Coraline mark an attempt to join the mainstream?

"That question used to piss me off," he says. "Shortly after I'd finished Neverwhere and Stardust, my first two novels, people were coming up to me and saying: 'How does it feel to be doing serious work?'

"I used to get quite stroppy about it. Sandman is 2,000 pages long, it took me 4000 pages of script to write those pages, it took me eight years to write. That is serious work! I didn't leave comics because I wanted to gain respectability. I left comics because there were certain skills I wished to gain. I wanted to teach myself how to do those things." (Considering all that braggadocio about the size of the piece, it is perhaps unsurprising that Norman Mailer is such a Sandman fan.)

But though the media may have changed, Gaiman's voice remains consistent. His stories tend to suppose a slippery supernatural undercurrent beneath the most mundane of events. In the Sandman, teenagers play football while Death, in the form of a sultry female Goth, chats them up. In American Gods, Odin and his fellow Nordic deities work in diners and gas stations. And in Coraline, a passageway leads a young girl into a disturbingly twisted version of her own world. Written for his own daughters, the slim volume took him over a decade to complete.

"It reminds me of a cliché," he says, in storytelling mode again. "The baker's family always lacks bread. The cobbler's family always lack shoes. The doctor's family are the last to get treated. If professionally what you do is write, then something you are doing in your own time doesn't get done.

"I showed it to an editor in the early 1990s and he said: 'You do realise this is unpublishable. It's horror for children and you can't do that. And you seem to have written a book that adults and children will both like. You can't publish a book for adults and children.' "

A raised eyebrow acknowledges the unmentioned Ms J.K. Rowling. "We had to wait for the landscape to change. I'd like to say that I was prescient back then. But actually I just wanted to finish my book."

The world that Coraline encounters features living toys, hordes of rats and a malign variation of the girl's mother who seeks to poke her eyes out with a needle. It is fairly grim stuff.

"In America a lot of the interviews were about how dark the book was," Gaiman says. "Over here, nobody is asking that. I think partly that is because two real young girls have just been killed by monsters. There's a realisation that presenting kids with a fuzzy, Barney-flavoured world where everything ends in a big hug is not necessarily the best thing.

"In Hansel and Gretel, there is war and famine at the beginning. And the two children's parents abandon them because they cannot afford to feed them. A witch tries to fatten them up and they are only saved when she is pushed into an oven. Children have never had a problem with this. There are good lessons here: your parents may one day find you expendable, not all adults mean you well."

One is reminded of cross-generational novelist Philip Pullman's recent complaints that contemporary adult fiction is afraid to address the big moral and philosophical issues.

"I think he's right," Gaiman says. "And story as well. Stephen King, a few years ago, sounded off about modern fiction: he said it was beautifully written, but there was no story. He said that it was like meeting a beautiful woman who is stupid. But plot and story are deemed important in children's fiction. They are not regarded as hangovers from pre-post-modernism which should be eliminated from the novel. Or whatever."

The film rights for Coraline have been optioned to animation director Henry Selick, the man behind The Nightmare Before Christmas and James and the Giant Peach. But Gaiman is not getting his hopes up. Though a dozen of the writer's projects have gone into development over the last decade, not one has made it to the screen.

"Of course, the thing you're really not supposed to say is that if you get the option renewed every year, it doesn't take long before you've made more money than you would ever have made if the film actually went into production."

Gaiman iscurrently juggling a number of projects, the most unlikely sounding of which is a screenplay of Nicholson Baker's uneasy sexual fantasy The Fermata, to be directed - and this is the really unlikely bit - by Robert Forrest Gump Zemeckis.

Sitting in his Gothic pile in Minneapolis, listening to Radio 4 on the Internet as he juggles calls from Mr Zemeckis and Terry Gilliam, Gaiman must occasionally consider the home life of the Hampshire accountant. How different things would have been if he'd listened to the man in the cellar.

Coraline, published by Bloomsbury, is priced £9.99 sterling