When I was younger, I lamented the fact that the only people you ever saw in flash cars were men with no hair
This is a gritty story of men and steel. Throbbing engines, open tops, leather upholstery, white-wall tyres, chrome bumpers: these things matter to men. For the past three generations, women have swallowed their yawns and said "customised hub-caps? How marvellous, sweetheart" to keep their darlings happy, and men have believed that cars increase their pulling power.

What's always stunned me is that men never seem to notice the other thing about cars, which is that the more time you spend around them, the less attractive you become. When I was younger, I lamented the fact that the only people you ever saw in flash cars were men with no hair. I believed that the purchase of horsepower was one of those sad things that men did when in denial about the onset of middle age. Now I think there's something far more sinister. The cars themselves are responsible. This belief began to grow during the sage of Frankie's Spitfire, and was confirmed the night I went to the car parade on Chelsea Bridge.

Frankie first. Frankie accessorises well: looks good in cufflinks and remains resolutely available for dancing. A couple of years ago, Frankie bought a Spitfire. "I've always wanted a sexy car," he said, "and I don't want to leave it for so long that I'm one of those old blokes in shades and a pigtail." So he laid down his life savings and brought home a gleaming red racing machine.

Frankie was a happy bunny. He drove around in his new acquisition with a smile as smug as Postman Pat's. But the car started hexing him. One started to see alarming changes in Frankie. It began with the leather jacket. This formerly sartorial man bought himself a brown leather jacket with tan knitted bit at the collar and cuffs. Then he started sporting a chunky gold identity bracelet. The following month, it was a pair of Aviator Ray Bans. After about six months, his previously taut little tummy began to develop a rounded quality.

I saw less of Frankie for a while. Then one day I bumped into him on the Edgware Road. He was driving a Fiesta and looked his old magnificent self, his lateral obliques as trim as the day he left school. "Hey!" I said, "what's happened to the Spitfire?" "Oh, that," he said. "I sold that. I kept wanting to buy Chris de Burgh tapes in service stations. And my hair started to fall out."

Would that self-knowledge came so quickly to others. For this is only half of the salutary tale. The other night I was stuck in a taxi in a traffic jam. The classic cars were cruising Queenstown Road in Battersea. These are the same classic cars that used to cruise the King's Road until the police told them not to. Now they convene to some unpredictable timetable like the third Saturday of the month as long as there's no full moon, and the police erect crowd barriers to prevent their followers getting run over. Not that there's much need, as the traffic in southwest London moves at about one mile an hour when they're out.

I'd been caught like this before and ended up paying a tenner for a fare that's usually four pounds, so this time I decided to leg it. It was about 11 o'clock: pub emptying time. On the bridge a group of skinheads leered and gestured at cars containing Asians. I wove my way through a crowd of a sort that I haven't been in since I gave up amusement arcades. Everyone was, without exception, spotty, slightly grimy, wearing nylon and drinking from those giant triple cans of Coca-Cola. It wasn't nice. It wasn't pretty, either.

At the roundabout which the cars circumnavigate, I encountered Dean. Or he encountered me. I was innocently leaning against a crash barrier and considering the advantages of eugenics when Dean sauntered over to have a try. I suppose I should be flattered, being chatted up by an 18-year-old, but somehow the tattie-fed complexion was offputting. Oh, and his two friends sniggering like Beavis and Butthead over by the garage.

"Hello," said Dean. "Come to see the cars, then?" I nodded. "It's great, isn't it?" "I haven't really seen anything yet, to be honest." "Don't worry. You will. You got a car?" I shook my head. "Do you?" "Naah, but my brother's got a Cadillac. He'll be turning up in a minute."

He was quite sweet, really, if a little over-hormoned. We talked about Peckham, where he'd come from, and Caesar's Palace in Streatham, where he claimed to go dancing, and I gave him a cigarette. The cigarette caused a volley of snorts from his pals. And then the cars came. Dinosaurs lumbering from the west, spewing exhaust fumes, once round the roundabout and off to the north. What a way to spend a weekend. All day Saturday polishing the chrome and dusting down the wooden dashboard, then a trip to the roundabout. Terrific.

Dean nudged me as a Lady Penelope pink thing rolled towards us and parped its horn. "That's Martin," he said proudly. Dean's brother was wearing dark glasses. I'm not sure how he saw to steer. He had on a white nylon T-shirt with a team-something logo. It set off his tattoo and the contours of his waist to perfection. Strands of hair were slicked from his upper forehead with some grease that reflected the streetlights. I guessed he was about 40: obviously a half-brother.

Dean waved, then folded his arms in satisfaction. "Great car," he said. "D'you like it?" "Mmm." I couldn't come up with a better response. "What does his wife think of him spending all that money on it?" Dean laughed. "Martin's not married. He's still playing the field. Well, it's stupid to get yourself tied down when you're 22, isn't it?"