With its icy waters and stomach-churning swells, the English Channel remains the Everest of swims. Peter Conchie sees the enduring appeal of an open-water classic

Shakespeare's Cliff rises above a stony beach midway between Folkestone and Dover. The white chalk is bright in the autumn sunshine and it looks like any other point on this section of the Kent coast. Just after breakfast on a clear morning last October, a lone swimmer stood briefly on the shore before slipping into the grey-blue water. With a stoic lack of fanfare, so began one of the most daunting journeys on Earth.

A few minutes earlier, Jonathan Paul, a 33-year-old American, had been on the deck of the Viking Princess fishing boat wearing trunks, swimming hat and goggles. Plugging his ears with globs of Vaseline, he dive-bombed into the sea and front-crawled to the beach to embark upon the final solo attempt of last year's Channel swimming season.

As the seagull flies, it is 21 miles from England and France. In 2005, 33 swimmers attempted the crossing, of whom 18 were successful. It may sound perverse, but for cross-channel swimmers there is no point taking the most direct route from Shakespeare's Cliff to Cap Gris Nez, between Boulogne and Calais. The tides mean that swimmers describe an "S"- shaped route as they are pushed off course by the first tide and back across by the second. Trying to stay in a straight line means wasted energy fighting the tides.

This intimidating journey is one many Americans make, in spite of a seascape that is comparatively dull compared with Florida or San Francisco Bay. "It's the Mount Everest of swims," JP remarks beforehand. "Just as any mountaineer will tell you that there are more challenging climbs, there are also more difficult swims, for example in Antarctica. But the reality is that the Channel is still the one to aspire to, and I think that's why people come from all over the world to challenge themselves."

And a challenge it surely is, and not merely because of the physical effort involved in this epic swim. Each day around 600 tankers and 200 catamarans, ferries and other vessels pass through the Channel in two wide lanes around five miles offshore. At one point I scan the horizon and count 18 ships. Other potential hazards include jellyfish, Force 6 winds and waves around two metres high.

In circumstances such as these, it pays to have good people around you. Reg Brickell is one of the Channel Swimming Assoc-iation's most experienced "pilots" and looks every inch the salty sea dog, complete with a single earring in the shape of an anchor.

It costs around £1,700 to secure his services. This is money well spent; Reg is a man you would trust to get you across black water in the dead of night. Each crossing has to be ratified by an observer from the Channel Swimming Association (CSA), the body who oversee unassisted swims. JP's observer is Andy, a former ABA schools boxing champion.

In the wheelhouse, Andy rolls another cigarette and Reg listens to the radio as the Dover coastguard announces JP's presence and the course of the Viking Princess to Channel shipping. "A wide berth is requested," goes the crackly announcement.

JP's coach is Leslie Thomas, a swimming teacher who also works with the swim-tour company Swim Trek. She isa channel- swimming veteran herself, but retired after 13 hours of her own attempt in 2004 with stomach problems. Persistently enthusiastic as only Americans can be, she has one of those clear and sonorous East Coast American voices that suggests she has spent a lot of her time making herself heard by schoolchildren in noisy swimming pools.

Leslie supervises JP's feeds every 30 minutes; after 25, she dangles a "5" sign overboard, giving JP encouragement that calories are ahoy. It is a sign that JP has the composure to acknowledge with a thumbs-up mid-stroke. When the feed is ready, she lowers a yellow smiley face.

Swimmers ratified by the CSA must make the crossing unaided and are prohibited from wearing wetsuits. The Channel Crossing Association have marginally less rigorous requirements; their rules permit swimmers to be fished from the water at intervals. Both organisations require solo swimmers to have completed a six-hour open-water qualifying swim in water below 15C.

As JP relentlessly slaps out his 67 strokes a minute, Leslie reveals the strategies that channel swimmers have used to fend off boredom and mental disintegration. One, a professor of economics, requested a fresh word puzzle when she stopped for her feed every 30 minutes, while other successful ploys include lulling yourself into a yogic, trance-like state. A P&O ferry passes, and as the passengers wave, JP flips to backstroke and waves back.

The world record for the Channel swim was set by Christof Wandratsch of Germany last year when he powered across in a barely plausible seven hours and three minutes. By my reckoning, however, a certain Henry Sullivan deserves equal admiration. In 1923 he set a record that still stands, with the longest successful crossing in a marrow-chilling 26hr 50min.

Early swimmers used to cover themselves with grease - goose, porpoise or mutton, according to preference and availability - to maintain their body temperature. The first crossing from France to England by a woman was in 1926 by an American, Gertrude Ederle. On this astonishing swim, she sustained herself with chicken and fruit and completed the journey in 14hr 39min, at the time the fastest by a man or a woman. It was the first crossing using the then new-fangled front-crawl technique as opposed to the breaststroke, and her time was not bettered for another 25 years.

The modern-day Channel Queen is Alison Streeter MBE, who has crossed the Channel 43 times, 10 more than any other man or woman. Meanwhile, George Brunstad became the oldest man to cross when he completed the trip last year at the age of 70. Apropos of nothing in particular, Brunstad is Matt Damon's uncle.

Most modern swimmers, JP included, forego the grease; research has shown that it doesn't really work. It is in the area of nutrition that things have changed most. Captain Matthew Webb, the first recorded person to make the crossing, in 1875, reportedly sustained himself with coffee, beer and brandy. JP has assembled an astonishing collection of nutritional drinks, foods and energy bars, with names such as Gu and Spizz. Appropriate really, as one aspect of open-water cross- ings nearly all swimmers must contend with is seasickness.

At 3.15pm JP has been swimming for five hours, yet only stops for as long as it takes to gulp a garish carbohydrate drink. On deck, his empty, white trainers seem to await his return. I ask Leslie about the ideal body-shape for swimming the channel. "Fat," comes the succinct reply. It helps with insulation and buoyancy, and while JP is far from meeting that description, physically he is chunkier than, say, a competitor in the Olympic pool. Reg talks dismissively of swimmers with washboard stomachs who may have looked the part but who have been back on deck two hours out of Dover.

Dusk is approaching, and as I sit on a coil of rope by the wheelhouse, England no longer dominates the horizon. As a result of JP's relentless effort, it has shrunk to a fuzzy chunk of land about the length of a finger. France appears wider now; the industrial chimneys of Calais are visible to the left, blue flashes from the lighthouse at Cap Gris Nez to the right. As the sun drops, a huge freighter looms ahead; its multicoloured cargo of red, blue and yellow containers on deck looks like stacked oblongs of Lego.

So what does it take to complete this awesome journey? Reg's steely grey-blue eyes twinkle and he shakes his head in wonder. "They've got to have something in them," he says in a South Coast burr. "It's blooming marvellous, really." Co-pilot Ray remarks that despite his tiredness, JP is not moaning, a sign that he may be successful.

With the sun now gone, JP stops to attach light-sticks to his trunks and the back of his head and swims into the night. This last part of the journey is the hardest, and JP complains that he feels he is going backwards. When Ray tries to encourage him with the news that he only has three miles to go, JP groans an agonised "Oh God!"

As France approaches, Reg and Andy board the launch of the Viking Princess and lead JP through the shallow waters to shore. What seems like an age later, JP reboards the boat: a successful Channel swimmer. After crossing in 11hr 49min, he looks pickled. He is groggy, and his face is badly swollen.

As I shake his hand below deck, he vomits into a bin. Many heaves later, he is deeply asleep in the foetal position. For a man who has just completed the 730th crossing of the English Channel, this must be one of the sweetest sleeps on Earth.

More details and information pack: 01245 473 581, channelswimmingassociation.com. For a list of ocean swims worldwide: oceanswims.com

Secrets of Channel success: plenty of fat, plenty of belief

Marcia Cleveland is the 445th person after Captain Webb (above) to have swum the Channel. In her book Dover Solo* she outlines her preparations:

Pool training: become used to swimming 1.5 to 2 hours at a time, interspersed with speed work. Progress to 3- to 4-hour swims, practising feeding in the water. Try and swim when there are other people in the pool, for companionship. Don't attempt more than four hours; it's too boring.

Open-water training: swim from mid-May through to the autumn, until the water temperature drops to 11-12C [the Channel summer average is around 15C]. Work up to 6- to 8-hour swims.

Qualifying swim: the Channel Swimming Association accepts six hours, but eight to 10 hours gives you a better idea of your strengths and weaknesses.

Diet/weight gain: Eat healthy high-fat foods, not junk, and avoid refined sugar - it will just make you tired. Don't put on too much weight, and teach your body to learn how to burn fat by regularly not eating for 6 hours or more before swims.

Psychological preparation: Yes You Can Yes You Can Yes You Can. Remember that each stroke takes you one stroke closer to France. You have this ability.

*Available at $30 outside the US. To order: doversolo.com