Typical. You wait years for an article about you. Then 20 turn up at once

Brixton bus garage had never seen anything like it. Like a latter- day south London Alamo, it was besieged on Monday by a force of hacks and snappers. Reporters were mobbing the cab of a 137 Routemaster bound for Oxford Circus, desperate for a word with the driver, who had had to sneak in to work via the back entrance to avoid the rat pack out front. To them, Magnus Mills was Clark Kent made flesh: bus driver by day, millionaire novelist by night.

"They didn't realise I couldn't possibly sit in the bus and pose," Mills recalls. "As I was rolling out, I told them, 'I've got to leave here at exactly 21 minutes to three. I can't leave early or late.' The press are always the first to complain if we're late. As I drove out, I saw that the photographers had all parked on the red route, blocking the way."

Such are the perils of becoming an overnight sensation in the middle of August. The Blairs are sequestered in the Casa Senza Paparazzi. William Hague has taken his baseball cap to a vacation in the States. Even Peter Mandelson's Ministry of Spin is having a break. It is at these moments that a news editor's thoughts turn from the sublime to the ridiculous, and grateful journalists leap on space-filling stories of flesh-eating bugs and deadly Euro-wasps. The British summer is marked by certain ancient institutions: Wimbledon, Henley and the Silly Season.

So what could fit more snugly into those acres of stories about house- destroying termites and vicious razorshells than the scarcely credible tale of the 44-year-old novel-writing bus driver whose debut work has been sold for "a cool pounds 1m" and is already being developed into a movie? Surely that one has "Silly Season" running through it like the word "Brighton" in a stick of rock? Cue reams of tired jokes along the lines of "any more fees please?" and "How much is a ticket to Hollywood? One million pounds."

Mills is not impressed with the precision of much of the reporting. Truth is the first casualty of the Silly Season. Far from the suggested pounds 1m, he has so far received an advance of pounds 10,000 from Flamingo, $5,000 from his American publishers, 20,000 francs from a French imprint and "under pounds 10,000" from a production company, Apocalypso Film, for a movie option. (Of course, that figure would rise substantially if the film went into production and, say, Leonardo DiCaprio decided to play one of the leads.)

The other thing that most reporters missed was that The Restraint of Beasts is a serious literary endeavour. Mills has not penned a knockabout novelisation of On the Buses - all wolf-whistling, chirpy Cockney conductors and fist-waving inspectors. He has written a spare and original black comedy about Tam and Richie, two work-shy rural fence-builders who leave murder and mayhem behind them wherever they ply their trade. Mills is keen to stress that "there are no detective inspectors or hospitals or any of that crap you get in modern novels."

The book has a deceptive simplicity; the author says that "unlike most novelists, I don't venture into analysing people's feelings - that's knocked half the potential readership on the head." It is also infused with a slow-burning wit. Lines take time to detonate. "I looked at her," Mills writes, "and realised that underneath all her clothes, she was completely naked."

The Restraint of Beasts has already been put forward by its publishers, Flamingo, for the Booker Prize. Word of mouth on the novel, to be published next month both here and in the US, has likened Mills to Kazuo Ishiguro and Paul Auster. One critic called this "a work of sinister brilliance". Its American publisher has dubbed it "Macbeth as filmed by the Cohn Brothers."

Philip Gwyn Jones, the editorial director at Flamingo, who won a bidding war for the book, is obviously an interested party, but he talks with real enthusiasm about Mills's "extraordinarily distinctive prose style". "It's not boastful or swaggering in the off-putting way that a lot of first novels are. It's very plain, which is unusual in this day and age. He uses few adjectives or adverbs. It is reminiscent of Beckett and Pinter. Magnus is a craftsman; he regards driving a bus as a craft.

"It has a lovely rhythm of its own. There are no internal monologues, no philosophising, and nothing that badges the book as belonging to any particular place or period. It's refreshing, when so many books are label- obsessed. The Restraint of Beasts is genuinely unlike anything else."

But these hero-grams (with their inevitable suspicion of "he would say that, wouldn't he?") pale into insignificance beside the praise heaped on the novel by Thomas Pynchon, the reclusive author of Gravity's Rainbow, V and The Crying of Lot 49, thought by many to be America's greatest living writer. Despite numerous inducements from publishers, Pynchon has not passed judgement on any work of fiction for several decades (his last recorded comment was about a book by the late Anthony Burgess).

Now he has chosen to break his critical silence (though not during a telephone call to Mills, as one inventive journalist claimed) by describing The Restraint of Beasts as: "a demented, deadpan comic wonder, this rude salute to the darker side of contract employment has the exuberant power of a magic word it might be impossibly dangerous (like the title of a certain other Scottish tale) to speak out loud."

For Mills, this was just one of many freaky events over the past few weeks. Tall, dark and handsome - yes, like someone out of a novel - he is an essentially diffident man who pauses for thought before answering questions. He has a sly, dry sense of humour, which has been a useful thing to have since his story broke in the national press. He has been invited to appear on everything from GMTV to London Tonight. His phone has gone "every 20 seconds", and on Monday alone his PR had more than 50 requests to speak to the "bookish bus-driver".

He has cast doubts on those press reports that claim he will carry on regardless as a bus driver (he alternates between the 137 from Streatham to Oxford Circus and the 159 between Brixton and Oxford Circus). After leaving Wolverhampton Poly some 20 years ago, Mills worked for six years as a fence-builder - a job that provided vital background information for the novel - and has spent the last 12 years on the buses. He wrote the book over two-and-a-half years between "spread-over" shifts (nine hours' work spread over 12 hours). A keen runner, cyclist and sailor, he has enviable reserves of energy; he gamely talked to me for an hour after a particularly hot and gruelling spread-over.

"Bus-driving is just a job. I could do it with my eyes shut - although I don't," he deadpans. "Most of my friends at work have been very supportive. All I've had is people coming up to me and saying, 'well done'. They think I've got a ticket to a better life. Bus-driving may look like an Ealing comedy, but it's pretty rough to do week in, week out in an inner-city garage. I like the idea of going up to some hillside on a motorbike and watching someone direct my story. But I might get in the way.

"It would be nice not to have to do nine hours a day at the bus garage. If they said, 'ring in at six in the morning and we'll see if we've got a bus that needs taking out', that would be ideal. But you don't get personal freedom if you work for someone. As a writer you can have a fantasy world - 'I'll work later, but I'll have me breakfast first'."

For all that, Mills pays tribute to his bus garage manager, who's been "very generous. He could have thought he had all his shifts straight and then along comes this driver who's written a novel and says, 'I need today off because I'm going to be interviewed by a national newspaper.' But he says they're not going to stand in my way, as long as I don't take the piss. It is good publicity for the bus company." I'll say.

But won't all this attention change Mills? He himself admits that "when I first met the film producer, I was all starry-eyed. One minute I'm a bus driver, the next they're making my film." Friends, however, reckon he'll cope. They consider him "extraordinarily level-headed". According to Gwyn Jones, "Magnus is an unusual chap. He has a finely honed sense of the absurd, so I hope he'll find all this Silly Season stuff entertaining. He's an accidental celebrity, and that will please him."

So far the only perceptible change after the torrent of hype is Mills's answering-machine message: it now plays a snatch from The Beatles' "Paperback Writer".

'The Restraint of Beasts' is published by Flamingo

on 7 September