Skateboarding? Been there. Snowboarding? Done that. Surfing? Yawn. Flying a kite is the adrenalin sport la mode, writes Jim White `I sell kites to people who work out with them' `We're always being assaulted by bloody great dogs'
In the close confines of Golders Hill Park in north London one recent Sunday, I saw an orthodox Jewish man wrestling with one end of a length of nylon string. At its other end was a kite which, despite a crisp wind, was lying on the ground, flapping weakly like an injured bird. The man was assisted in his enterprise by his mother, whom he was blaming loudly for the failure of the kite to fly.

"When I say to let go," he shouted, handing her the kite as he tried once more for take-off, "you let go." So she did, and the kite nosedived limply into the turf.

"No, no," the man yelled. "I haven't said to let go yet."

"But you just said it."

"No, I said I was going to say to let go. When I say to let go, then you let go."

"Again? But I have already." After each launch failure, the woman, perhaps noticing the small crowd that had gatheredto observe progress, suggested they abandon the exercise and go home. Each time he would refuse, angrily pointing out that he was doing it for the children's benefit, that he would not give up until he got the thing flying.

"But, Moshe," said his mother. "The children, they go off to feed the ducks about half an hour ago."

According to those who know, this is a common sight in Golders Hill Park: kites rarely take off under Orthodox control - not so much a genetic problem as the fact that it is hard to launch one when you are loaded down with half a dozen supermarket carry-out bags filled with picnic food.

Not that the residents of Golders Green are uniquely incapable. Now that the weather has cheered up, men in muck sweats, from Town Moor in Newcastle to the Sussex Downs, can be seen every weekend tugging at grounded kites as their children stand around wondering why they bother.

Except, that is, on Hackney Marshes in east London. Last Sunday, much of the population of the borough was spread across the hundred football pitches of the Marshes to watch two tower blocks being demolished, blown down in an expert and spectacular crumple as if constructed from playing cards.

In front of the demolition, out in the middle of the open space, however, was an even more astonishing sight. Four multi-coloured delta wings danced and darted across the sky in the kind of rigid, rhythmic formation that the Red Arrows spend years perfecting. They looked like low-flying UFOs, moving slickly among each other in graceful circles and swoops, the only sound a low rasping noise, like a child running a stick along railings.

They were, though anyone whose only experience was in Golders Hill Park would not believe it, kites. At the other end of each string were four men moving with the grace and nimbleness of Chinese athletes.

Airkraft, the country's top kite-flying team, the quartet who have come second in the last two Kite Flying World Championships and intend to go one better this summer, can be found on the Marshes every Sunday, perfecting their spins and reels.

"You need a bit of mental co-ordination to fly a kite," said Jeremy Boyce, founding member of the team and, like a surprising number of kite-ists, completely hair-free. "Golders Hill Park is the worst place."

But don't you need to be on a hill? "No. What you need is an open space, free of trees, and a clear wind," said Jeremy. "Parliament Hill is the traditional place to go in London, but now kiting's so popular it's chaos up there. The only reason to go is to snigger at all the lines tangling up" - or, in Jeremy's case, to go and see some of his kites in action.

Five years ago, he was bitten so badly by the pastime, that he decided to pack in his job as sales manager for Rough Trade Records and open a shop, "High As A Kite", in Stoke Newington dedicated to his calling. It has become something of a meeting point for London's kite anoraks, or radicals as they prefer to be known. Stand for an hour in his shop, surrounded by kites, shaped like ghosts, elephants, birds and tropical fish, and yards of nylon, and you will see more reversed baseball caps wandering in and out than at an Eric Cantona lookalike convention.

"I sell kites to people who windsurf who like to have something to do when the wind is not strong enough or too strong for surfing. I sell kites to people who work out with them. I sell kites to people who take off on them. It definitely has a radical sporty image, and some of the new kites are so dynamic that people want to measure their skill against someone else."

Hence the burgeoning competitive kite-flying circuit, on which Airkraft is firmly established. So good are they, in fact, that they are regularly flown to competitions in France, Australia, America, to give demonstrations of how it can be done.

The team only came together two years ago, formed from regulars at Jeremy's shop. It consists, with a certain symmetry, of brothers James and Carl Robertshaw, who have hair, plus Nick Boothby and Jeremy, who don't.

They have become so good in such a short space of time because they practise with a dedication bordering on the obsessive: every Sunday from dawn till dusk, as well as twice on weekday afternoons (easily arranged, James is a student, Carl unemployed, Jeremy hands his shop over to his assistant and Nick is an actor, so is often resting).

"If you want to get to the top in a sport, you have to put in the hours," said Jeremy.

They arrive at the Marshes burdened down with bags of kites (Nick has 31 competition kites, James eight, Jeremy a whole shopful) which they anchor down at strategic points around the football pitches. To watch the team practise is to see grace in action, a kind of Torville and Dean of the air, completely at odds with their surroundings.

Hackney Marshes is the home of bad football, where the games that go on around them are punctuated by the yelling and swearing of fighting team-mates and the frequent bleat of ambulance sirens. During Airkraft's sessions, all is tranquillity and calm (karma, perhaps). You will hear only one team member shout - generally Carl, issuing crisp, staccato orders: "Brake, turn, stall, land."

"We do fall out if one of us cocks it up, but we don't shout," said James. "There just tends to be a sort of atmosphere." Besides, it would be pointless trying to yell blame above the noise of the kites. This angry growl as they tear through the air is the explanation for one of the less expected side-effects of formation flying - dog attacks.

"We're always being assaulted by bloody great big dogs," Jeremy complained. "The sound really sends them. And if you complain to an owner after their dog has savaged a kite, they just seem to blame you for provoking them."

The problem of flying kites exciting dogs is not one they encounter often at Golders Hill Park.