Halfway through the second stage of a 330-mile bike ride from London to Paris, our rainbow-hued peloton sweeps through an ancient hamlet of biscuit-coloured stone houses. A group of school kids has clambered on to the wall of their playground and is chanting and waving in the sunshine as we pass in a blur of whirring wheels and glinting pedals. One little boy catches my eye and yells: "Allez, monsieur, allez!" while his classmates all scream in delight: "Plus rapide, plus rapide!" The moment flashes like quicksilver, but I know it'll be one I'll savour for months to come.

The Londres-Paris bike race, or the L2P as it's now often called, is in its eighth year and has gained a reputation for being "the professional cycling event for amateur riders". It takes place over three 110-mile stages and has climb and sprint sections as well as a timed "yellow jersey" competition. It's the closest most club cyclists will ever get to experiencing life in the Tour de France… well, it would be if we kept going for another 2,000 miles and doubled our speed. But those are mere details.

Certainly the L2P looks the part. There's a fleet of Skoda support cars in full race regalia (240 Octavias and Superbs are currently following the actual tour) and 45 mustachioed motorbike outriders who effortlessly organise a system of rolling road closures which ensure we sweep across junctions and through red lights as if we have diplomatic immunity. There is also a 130-strong crew of mechanics, physiotherapists, cooks, PRs, cameramen, bag handlers and drivers looking after us. There are musettes and energy gels and a dozen race captains – and there are of course drugs, too, but these are all consumed in 500ml beer glasses at the end of the day.

And then there are the rouleurs – this year 365 are taking part. It's all shaved legs, mahogany-smooth calves and beautiful bikes sculpted from carbon and titanium. I had been tempted to borrow my wife's Ladyshave, but as I was already entering a world I wasn't au fait with I decided to stick with my aerodynamically disastrous leg fur. Besides, I was still shaken by the events of that morning. My roommate, who I'd only met the day before and who knew so much about cycle lore that I was surprised to see his pyjamas were not made of Lycra, had peered at the inside of my cycling shorts and asked if I wanted to borrow his "bottom butter". When I'd looked blank he'd produced a tube of what looked like Primula cheese and squirted the cream all over the crotch. He then patiently explained that the lubricant would spare me the worst effects of sitting on a sadistically thin saddle for the best part of seven hours a day.

Each year the L2P attracts some of the biggest stars from the world of sport. Lining up at the start of the 2011 race was cycling legend Stephen Roche, who has won both the Tour de France and the Giro d'Italia in his time. Magnus Bäckstedt, a winner of the Paris-Roubaix, was alongside him, flexing his colossal thighs, as was Will Carling. Nigel Mansell was there, too. He'd arrived with a pair of young riders to push him up the hills. "No, of course it's not cheating," he'd laughed as they propelled him effortlessly past me on the day's first long climb.

But the cycling celebrities were not here to grandstand – they were here to be part of the peloton, happy to be working alongside the rest of us to keep the group's speed up. Individual cycling is an intensely competitive sport, but a well-drilled peloton will always be more than the sum of its parts. So pedalling alongside the likes of Stephen, Magnus, Will and Nigel is new-dad Matt, who's flown over from Singapore just for the event. There's a group of 11 who have come from Colorado "for some flat riding", and others still from Jersey, Australia and South Africa. There's also Stuart and Debbie from Dunblane, who are "doing something memorable" for their 25th wedding anniversary, and Paul, who is riding for a personal charity linked to his son's illness, and then there's Joanna and Henry and John and Kevin and Michelle… At times the event seems more like a high-speed cocktail party than a serious road race.

The L2P is my first real chance to sample peloton life. There is so much unspoken etiquette to riding in a bunch that in some ways it has been like joining the Masons. The more experienced riders have been passing on their road knowledge to us newbies and I've quickly learned the hand signals cyclists make behind their backs to alert following riders of potholes and obstructions, of parked cars and speed bumps; calls of "slowing" or "gravel" or "stopping" shouted over shoulders echo along the line. I toyed with introducing a new sign for "Road kill ahead", but no one seemed interested in my upturned hand…

At last, after three hard but exhilarating days in the saddle, we ride into Paris. This is the spine-tingling moment we've all been waiting for. The capital has played host to the final stage of the world's greatest bike race for more than a century, and cycling legends from Jacques Anquetil to Eddy Merckx and Bernard Hinault to Lance Armstrong have raced along the very roads that we are now pedalling.

The peloton, stretched at times to more than a mile long, flies along the historic streets. Cars blow their horns, church bells ring, a bride gets out of her stopped wedding car to cheer as we sweep past. We turn on to the Avenue Foch, one of the cobbled boulevards that leads up to the immense bulk of the Arc de Triomphe – the scene of Stephen Roche's epic triumph in 1987 – and then turn down along the river Seine to finish in the shadow of the Eiffel Tower. There's laughter and hugs, the popping of champagne corks, and few without tears in their eyes.

"Honest, it's just the hay fever," says the sobbing Matt.

After a slap-up dinner with too much wine, rousing speeches and bouts of backslapping, I load up my bike and head for the Eurostar and London. It took me 21 hours to get to Paris – and just over two to get back.

I bid farewell to my new peloton buddies at St Pancras station on the Sunday morning and set off to slowly cycle the seven miles back to my home in south London. At one point I swerve past a large pothole and instinctively gesture a warning for the riders behind me… I smile stupidly and then say to myself: "Allez, monsieur, allez!"

Essentials

For details on how to enter next year's L2P, go to londres-paris.com. This year's event cost £960, which included all meals, accommodation and travel costs. To watch a film of the race first shown on British Eurosport, go to http://bit.ly/london2paris