Damn the dog. Bullet, a young Rottweiler, is sticking his wet nose under the lid of Bryan Smith's food-cooler, threatening to eat his lunch. Smith wrestles with his pet with one hand, keeping the other on the wheel of his light blue Dodge minivan. It is tricky because they are travelling at 45 miles an hour. As the van climbs a gentle hill on Route 5 in western Maine, it begins to swerve. It doesn't slow down.

On the other side of the crest, a man is walking. It is mid-June and he is taking his customary four-mile constitutional through the countryside near his summer retreat. As always, he has a book under his arm. Today it's The House, by Bentley Little. Known locally as an eccentric, he likes to read and walk at the same time, but not on this short stretch along Route 5. Here, he pays attention and sticks to the hard shoulder, going against the traffic. The hill's brow means that he cannot see the slaloming Dodge on the other side.

Fans of Stephen King, master of the Gothic novel, will not need to turn the page to discover what happened next. They know the story. This was 19 June and the unsuspecting walker was King himself. Seconds later the van careered into view and slammed into him, head on. King bounced from its windscreen, clean into the air, and landed in a grassy ditch. His injuries were severe - his legs were smashed, a hip was dislocated, part of his scalp was torn from his skull. "It just happened," King recalled. "Bang, it was there. I woke up with my lap on sideways." When an ambulance arrived, he was alive - but barely.

The accident made headlines around the globe. It was not just that the world had nearly lost one the most successful writers of all time. (King's output includes 53 books, nearly all best-sellers, and he has sold no fewer than 300 million copies. They reportedly bring him an annual income of $40m.) There was also the chilling overlapping of reality and his art. Here was King, 52, suddenly catapulted into the same chamber of horrors that he had been purveying through his pen for so many years. Road accidents, moreover, had long been a favourite tool. Among his creations is "Christine", a malevolent '57 Plymouth bent on killing anyone who gets between her and her owner. In Thinner, a fat lawyer runs down and kills a gypsy woman, whose people put a curse on him; the man is doomed to waste away, regardless of how much he eats.

Most famously, King is the author of Misery, one of many of his books to have become a Hollywood film. It is about an author who suffers terrible leg injuries in a car accident. He is rescued by a devoted fan named Annie Wilkes, played by Kathy Bates at her most matronly sadistic, who keeps him prisoner until he writes a novel to her specification.

The headlines have faded, but this story is not yet over. King is still battling with his injuries. On his way to hospital he suffered a collapsed lung; the medics have since admitted that they thought he would die. In the first few weeks after the accident he had six major operations. He still uses crutches; he has been told that by next summer he may be walking at 85 per cent of his previous capacity.

Happily, he is not cursed with a carer like his frightening creation Annie Wilkes. By his side throughout has been his wife of more than 20 years, Tabitha King, another writer. Nor has the accident itself been entirely disposed of, or its circumstances. In this still unfolding narrative - as complex as any King plot - the twin fates of Bryan Smith, the driver, and his minivan remain unresolved.

First, there is the van, which now belongs to King. It recently emerged that after the accident he dispatched his lawyer, Warren Silver, to purchase it from Smith for the modest sum of $1,500. (It is a 1985 model and, for obvious reasons, is severely battered.) What, you may ask, does King want with it? He told the Bridgton News, the local paper in the part of Maine where the accident happened: "I'm going to take a sledgehammer and beat the crap out of it!"

King doesn't yet have the strength to wreak this unusual revenge. But rumours are rife in Bangor, where King and his wife have their principal home - a creepy Victorian mansion with the requisite cobwebs and locked doors - that the public will be invited to attend, and charged for the privilege. The proceeds, the rumours say, will go to charity.

Bangor, 20 miles inland from the Atlantic and just an hour's drive from the Canadian border, is a town with few distractions. It has an international airport, a refuelling stop for transatlantic flights before the age of long-range jumbos, where planes with unruly passengers - sometimes from Britain - are deposited into the care of American cops. Otherwise it has Stephen King, who first made the town his home 20 years ago. He gives it an unlikely gloss of celebrity as well as money. Recently, his philanthropy extended to a $2.5m gift to the Bangor library.

Smith, meanwhile, has apologised on behalf of himself and Bullet the dog. "I got distracted," he told the Bangor News. "It was one time, and one time only. I'm very, very sorry." But that may not be enough. It is Smith's misfortune that he has a long record of driving violations. As for King, he has said that he is not contemplating anything like a lawsuit, but he is campaigning loudly to have Smith's licence suspended for life.

The state of Maine is taking the affair even more seriously. On 30 September, a grand jury in Bangor charged Smith with aggravated assault. Such a charge is rare in a driving case and could carry a sentence of 10 years' imprisonment. Smith's trial is to start next spring. At first, sympathy in Maine was with the Kings, who are virtual patron saints of the state. But recently emotions have begun to turn. Letters to the Bangor News have been running about four-to-one behind Smith.

That the people of Bangor should be voicing sympathy with Smith, rather than King, seems surprising. It is not that in Maine, where fish and trees traditionally provided most people's income before the growth of tourism, people are especially fickle. But their relative isolation makes them wary of anything that smacks of the big city. Nobody, not even King, should be allowed to trample the small guy.

"The pendulum has definitely swung back against Mr King and for Mr Smith," Dick Shaw, the paper's editorial page assistant, confirmed yesterday. "At first, most of the letters were quite sympathetic to King, but after a while people began to think that King's celebrity was having an unfair bearing on how justice would come out."

The love that Maine people feel for King may become eclipsed by their natural instinct to back the underdog. Some letter-writers suggest that if it had been King at the wheel and Smith had been the victim, no charges would ever have been brought. Prosecutors in Bangor insist that the trial will be unaffected by the identity of the man run down.

Mr Smith's lawyer, John Jenness, is unconvinced. He notes that following his treatment at two Maine hospitals, Mr King made donations to them amounting to $200,000. Jenness contends that that act of generosity alone will bias the jury in the writer's favour. He is also trying to have the trial heard in a state outside Maine, where feelings about King are less passionate. District Attorney Joseph O'Connor ridicules this, pointing out that King is famous everywhere. "Realistically, where will you change the venue to?" he asks. "Timbuktu?"

What of Mr King's writing, meanwhile? Ten days ago fans had a fright, when the author gave his first televised interview since his accident. Talking to Katie Couric of the Today show on NBC, he revealed that when he tried to resume work after the summer he found himself almost totally blocked. "It was as if I'd never done this in my life. It was like starting over from square one." He even intimated that he might never complete a new work again. Last week, though, he posted a statement on the official Stephen King website contending that the media had taken some of his comments to Couric out of context. "My endurance is much less than it was, and my output has been cut in half, but I am working," he insisted.

If so, how long will it be before Bullet, Smith, the van, the sledgehammer and his lap skewed sideways make it into a best-seller? "Sooner or later," he told Couric, "everything goes in."