Arthur Pendragon: The once and future king

King Arthur is at it again, putting himself on the line for yet another lost cause. In this case the cause is an insignificant parcel of dusty chalkland between a nearly finished park-and-ride scheme, at Bar End near Twyford Down outside Winchester, and an already existing scheme only 10 or 15 yards away. The problem for Hampshire County Council - the organisation funding the work - is that the disputed plot lies between the two schemes, and that work on the new facility cannot be completed until the two are joined up.

Arthur and the other protesters have roped off the area and put up notices under section six of the Criminal Law Act 1977, declaring this as their home. They are happily ensconced in a mix-and-match tarpaulin- covered shelter under a monumental wooden A-frame, surrounded by all the accoutrements of open-air living: a flickering, smoke-blackened wood-burning stove, an extensive kitchen area made of wooden palettes, strewn with all the necessities of outdoor cooking, along with tents, mattresses, sleeping-platforms, bedding, chairs, makeshift beds and cushions, the whole jumbled assemblage covered in a fine white dust from the extensive workings in the network of defensive tunnels that underlie it all.

Not that you are likely to find Arthur down a tunnel or dangling from an A-frame. He is too portly for tunnels and whenever he tries to climb his knees give way. His main role seems to be attracting publicity to the cause, by burning cakes in the middle of the road under the statue of King Alfred in Winchester, thereby stopping the traffic and getting himself arrested. Or chaining himself to the railings outside the Guildhall, and getting himself arrested. Or going on a sit-down protest outside the entrance gates of the work site, and getting himself arrested. Getting himself arrested is one of his principal skills. You can add to that the mind of a barrack-room lawyer with a highly developed sense of justice. In his long career, Arthur has been arrested 39 times, with 38 not-guilty verdicts.

This is Arthur the 21st-century eco-warrior, not Arthur the Dark Ages King of the Britons: an Arthur who sees the battle for justice as taking place within the English courts of law.

We've been here before.

Twyford Down was the site of the infamous M3 extension in the early Nineties, and the scene of the most dramaticroad protest in the UK. The significance of the new park-and-ride scheme for the protesters is that it is built on the route of the old A33, reclaimed as meadowland after the motorway was finished, and promised to the people of Winchester "for posterity" as compensation for the loss of countryside caused by the original work. As late as January 1994 a spokesman for the Department of Transport was writing to Gerald Malone, then Tory MP for Winchester, to assure him that no such work was ever going to take place. So much for that.

There is something reassuringly familiar about the sight of tarpaulin-covered benders and lock-ons and tree houses and soaring aerial walkways made of polypropylene rope - so much so that we tend to forget how startlingly original this form of protest was when it first entered the public consciousness more than 10 years ago. And by the same token, some people have even got used to the sight of a middle-aged, bearded biker with long, greying hair, wearing a white frock, carrying a sword and claiming to be King Arthur. He has a way of lurking around on the periphery of the respectable media and making his presence felt.

He is hard to miss. He's done the Clive Anderson show, and Richard Littlejohn and, more recently, represented the Druids on Jeremy Clarkson's Top Gear in the "fastest faith" contest, where he hurtled around a race track in a souped-up rally car, looking mildly undignified in his spectacles and racing helmet. He came third. More seriously, you may have registered one of the many campaigns he has been involved in over the years: from the original Twyford Down protests to the Newbury bypass, from the dockers' march to the campaign to free Stonehenge for the annual summer solstice celebrations.

The question that will have occurred to some of you at least - as it occurred to me when I first heard about him - is the obvious one: is he mad? Does he really think he is King Arthur, and if so, in what form: as his descendant or his reincarnation? And if he is not mad but merely a self-publicist in fancy dress - in the tradition of the Monster Raving Loonies, say - then who exactly does he think he is kidding?

The first question is easy to answer. The difference between a paranoiac suffering from delusions of grandeur and Arthur is simply this: that whereas the paranoiac feels deeply persecuted because the rest of the world does not accept his claims, Arthur Pendragon does not care one way or the other whether you think he is King Arthur or not. Ask him who he is and he will tell you. "I'm the nutter who thinks he's King Arthur."

As for the rest, Arthur has a line to explain it. "There's a pre-Roman Arthur, and a post-Roman Arthur," he says, "and a post-Thatcher Arthur. And that's me." In other words, if there is a spirit of Arthur dedicated to the protection of these isles, then he is the Arthur who represents it right now.

Of course, there was a pre-Arthur Arthur too. He was born John Timothy Rothwell, the son of a sergeant in the British Army (a war hero, with several distinguished medals to his credit). Arthur was also a soldier at one time, then a biker, then a builder, and then a biker again. He once walked away from a job and a house and a mortgage - leaving the keys in the front door, a car in the drive, a TV and a stereo in the living-room - got on his bike and roared off into the sunset, without a word to anyone. This was all before he assumed the royal prerogative.

As to how he came to name himself King Arthur: that happened in a grubby bikers' squat in Aldershot in 1986, when one of his troupe handed him a book about the legendary king, and told him that that was who he was. It had something to do with the bikers' creed. They saw themselves as warriors anyway, and Arthur was already the leader, even then. He was sufficiently impressed with the gesture to have gone on practising the part ever since.

Events have only accumulated to confirm his role: from acquiring the actual sword made for the film Excalibur to having the sword acknowledged in the English courts, by being allowed to swear on it in place of the Bible.

Arthur and I have collaborated on his autobiography. And something that occurred to me early in our collaboration was that he has always been in uniform: firstly as a soldier, then as a biker, and, latterly, as a king. I have rarely seen him without his robes, when he is not "on duty", as it were. When I have seen him dressed in any other way I think of him as being in civvies. You might reasonably wonder what he wears under his robes. He wears ordinary clothing: jeans and a T-shirt, usually second-hand or cast off by his many supporters. Sometimes this can lead to problems, particularly when the clothing does not fit. I have had the dubious pleasure of seeing the king with his trousers down on several occasions.

Arthur is also perfectly at ease with himself. The following took place when we were first working on the book. I was reading Malory, just to get a flavour of the background story, and hadn't yet managed to get any words on paper. I went to meet Arthur at a pagan moot being held in the Conway Hall in Red Lion Square in London. Arthur was due to introduce a film that had been made about him, but - it being early yet - we decided to head for the pub.

It was Sunday lunchtime, and the pub was packed. And there, suddenly, was Arthur, in full regalia, with his chain-mail headband and his cloak, with his embroidered tabard and his hooded robe, complete with leather straps and boots and chunky pagan jewellery - and the whole place erupted into laughter. "Look," someone said, cackling and pointing. "It's King Arthur!"

The pub was full of Geordie steel-erectors, and within 10 minutes they were crowding round him asking him questions, plying him with drinks, laughing, bantering, offering their services as security for the next Stonehenge ceremony, generally enjoying the uniqueness of the moment. It is not often you meet a mythological king on your day off.

Arthur, of course, was talking about the building work he had done in his previous incarnation. "What?" one of them said, "you mean before you went loopy?", and then bought Arthur yet another drink. So you can say this about Arthur's appearance: it saves him having to buy a round.

We all need heroes, people who are willing to stand up for a cause. And the British love eccentricity. We love absurdity. The Monster Raving Loony Party might never get themselves elected, but we would be disappointed if they were not there. Arthur's willingness to make a spectacle of himself can be seen as part of that tradition. What makes Arthur's stance slightly different, perhaps, to that of some of the other egotists wandering around claiming titles, is that Arthur hasn't let it rest there. He has gone out and done something with the persona, using it as a guise in which to publicise environmental and cultural causes: identifying himself with the great British historical tradition of wearing fancy dress to make a point. We can see him perhaps as a fellow traveller, so to speak, of the Luddites with their fictional captain, Ned Ludd, or the 19th-century Welsh proto-anti-capitalist protesters, the Hosts of Rebecca, who dressed as women.

It is some measure of the man that Arthur has made it his life-long quest to take on the impossible. The Winchester protest is only one such example. What other political figure would dare to put themselves out for such a hopeless cause?

The first Twyford Down protest took place under a Tory government, with a Tory MP representing the constituency. This new protest takes place under a Labour government, with a Liberal MP playing his part. Which goes to show - as the old anarchist slogan has it - that it does not matter who you vote for, the government always gets in. And with the present government having revived all the old Tory road-building plans, it looks as if we are set for another lengthy round of disruption and dissent, with King Arthur playing his usual, very public, part.

The last time I saw Arthur was in the tatty shelter beneath the stars next to the unfinished park-and-ride scheme at Bar End. We were drinking, as usual. Arthur has this habit, what he calls "burning the journalist". By "the journalist", he means me. So as I talk he leans down, flicks his lighter and applies the flame to the bottom of my trousers. This is such a regular occurrence that I hardly notice. It takes a while before cotton burns and I can usually catch it before too much damage is done. Only this time I happen to be wearing trousers made not of cotton, but of man-made fibre, and before I know it one leg is on fire, dripping burning, noxious liquid onto my skin, and I hop around on my other leg, batting the flames with my hand.

You can say this about Arthur: he will allow no one to stand on ceremony. I still have the blisters to show for it.

'The Trials of Arthur' by Arthur Pendragon & Christopher James Stone (Element Books, £12.99)