Drunken, obese and grumpy, Thraxas is a failure. Once, he dreamed of being a sorcerer. Instead, he was sacked from the palace for reasons related to alcohol intake and insubordination. Thraxas lives in the medieval city of Turai. And his fictional antecedents? Oddly, the ice cool private investigators Sam Spade and Philip Marlowe.

"There had been quite a few cross-genre detectives already, in Rome and the medieval world, and I think my first thought was it would be fun to put a detective in The Lord Of The Rings," says Thraxas' creator Martin Scott, "just drop him exactly into that world."

Not that Scott's original plan came to fruition. Instead, as he wrote the first book, the characters, both Thraxas and his female sidekick, Makri, began to takeover. "It was meant to be more noirish when I started, because I like Dashiell Hammett and Raymond Chandler," says Scott, "but that didn't really work because Thraxas and Makri were kind of like a comedy double act - so they became funnier really."

As borne out by Thraxas and its seven sequels, it's a double act that's provided Scott with rich material for lampooning sword-and-sorcery tales. In the latest, Thraxas Under Fire, for instance, Turai is on the verge of falling to Orcish attackers. The shallow, self-obsessed Thraxas, though, is mostly concerned with raising cash to enter a card game.

In contrast to Thraxas, Makri is smart and serious, constantly lobbying to get into the city's university, despite that institution's dim view of women getting an education. Makri is also a champion gladiator of formidable personal charms.

"When I was younger, as well as liking Conan, I was a fan of Red Sonja," says Scott. "so I do firmly believe that if you're writing a fantasy book, if you can't have an axe-wielding barbarian woman in a chainmail bikini - and the chainmail bikini is very important - then there's no point in writing it, really.

"Which, incidentally, I was criticised for one time on Radio Four. I went to some damn programme and there were three or four other fantasy authors and they asked the other three normal questions about their books. Then the presenter came to me and she said, 'Well I see you've somebody in a chainmail bikini, that's a bit sexist isn't it?', leaving me quite nonplussed."

The BBC doesn't understand, but SF fans do. In 2000, the first novel in the sequence won the World Fantasy Award. Not bad for a debut/except Thraxas wasn't actually the author's debut. Scott had been writing since the 1980s as Martin Millar, trailblazing the way for the likes of Irvine Welsh with a series of novels tracing the adventures of punk rock squatters in South London.

"They were influential without ever selling anything," sighs the deadpan Scott. "When I wrote these books - Alby Starvation or Lux The Poet - I remember if I ever got any reviews, or interviews, or any attention whatsoever, it was always in music papers. It wasn't like I was writing about bands, they were just novels, but the NME or The Face would run an author interview occasionally. I'm not sure why that was, but I don't think there were many books set in that kind of world at the time, maybe that's why."

This may sound far removed from the world of comic fantasy, but the Glasgow-born author says his Millar and Scott personae aren't that separate.

I suppose a lot of fantasy writers would say this, but as the characters are the main thing, that's really just the same as in any book," he says. "I like writing about people and their friendships, as that's much the same in a Thraxas book as it would be in a Martin Millar book, it's not a big departure."

To look at that from another angle, Martin Millar books are hardly rooted in traditional realism. Instead, all of Scott's writing is shot through with a sense of heightened reality where the humdrum and the extraordinary live side by side. Scott's best-loved book as Martin Millar is arguably The Good Fames Of New York, a tale of drunken little people and Johnny Thunders' restless ghost searching for his old guitar in the Big Apple. Despite its popularity, it's a novel that induces some grumpiness in Scott.

"The Good Fairies, ..is a. big fucking frustration," he says. "It's out of print in Britain. Every week I get emails from people asking where they can get a copy and I have to say, 'You can't.' Inevitably, they email me back triumphantly a week or two later and say, 'I've just found a copy on eBay.' And I think, 'Well great.'

Continuing the fantasy theme, Scott claims his latest Martin Millar opus, The Lonely Werewolf Girl (currently in need of a publisher...), was influenced by his obsession with Buffy The Vampire Slayer, a show Scott says he loved because it was fiction reduced to its "enjoyable bits". Buffy even inspired Scott to write a Brit-set teen film script that was greenlit, only to disappear into development hell when Sky pulled funding before Scott received the "vast, huge cheque" due on the first day of production.

Somehow, it seems like a typical story for a man who should by rights be regarded as one of Britain's foremost cult heroes. Not that Scott's complaining. "I would frankly say I never did as well as I hoped I would," he says, "but I wouldn't complain because I've kept myself with my writing for years now, which a lot of writers never manage.