Fear is no stranger to men in their 40s. Between us our party of three have outsailed ocean storms, ridden Thorpe Park's scariest rides, forgotten to pick up the wife's dry cleaning. But in every adventure I have had, I have felt to some degree in control of my destiny.
Not so now. We're hurtling towards bend six, which is important, because that's where, according to Jacques Duc, the pilot of the bobsleigh we are strapped into, says "it picks up speed". We'll soon know what three times normal gravity feels like, and whether we're cut out for the BBC's Blue Peter.
"We" are Paul, Stephen and Martin, "los tres amigos", three friends who share down time doing silly things such as learning to surf and playing football. A post-match pub dare has landed us in La Plagne, in the French Alps, to ride the Olympic bobsleigh run.
Our day starts at a practice track beside the Isère river. There we meet Jacques, a past international bob and skeleton competitor. He must have made at least 10,000 descents in his sporting life, he reckons, but his passion has never dimmed. We spend a happy hour being shown how to do racing starts, and jump in in sequence, using a wheeled bob on rails. We make a decent fist of it, and Jacques seems pleased with our enthusiasm.
So we head up the mountain for a closer look at the real thing. La Plagne's course was built for the 1992 Winter Games. It is much in demand among international racing teams, and several are here today – Germany, Monaco, Switzerland and Liechtenstein. During the professionals' lunch break, we get to walk the run for a close look.
It's slippery. The big curves are three metres high, like great flat walls. Jacques points at the scratches on the ice surface, interpreting good and bad lines. We gulp a bit – he is pointing above his head, where we'll shortly be travelling sideways at 90 degrees to the ground. We giggle and bump into each other in a not very Olympian way.
"You may be surprised here," says Jacques. A face from a glamour calendar stares out at us from the ice – a test to see if sponsorship ads might be frozen into the track. But he is referring to two curves separated by about 20m of straight, that will flip-flop us from side to side like plaice being filleted on a fishmonger's slab.
We encounter a maintenance team using things that look like brooms but are actually planes on sticks that scrape the surface flat. They have tubs of snow to fill any divots. Finally, we stare up the long rise to the finish.
I ask how long it will take to get here.
"About a minute."
How long is the course?
"A mile – with 19 bends on the way."
We drive to the start, just below La Plagne's 1,800m resort station. At the entrance, racers are polishing runners and making adjustments to nose cones. As we watch them practise, my mind wanders back to the reason I wanted to come here. As a child I was a big fan of Blue Peter and the daredevil stunts its presenters got up to. I was particularly taken by presenter John Noakes's attempt at the bobsleigh. His trip ended in disaster but my youthful mind filtered out that bruising outcome. Obligingly, the Swiss team rack up the tension by crashing.
"He's OK," says Jacques, back from the control room. "He just lost something off his shoulder." What? An arm?
All too soon, after we've slipped on tight racers' bodysuits, our turn comes. Our ride is a standard four-man bob minus the retractable pushing arms – it is too dangerous to let novices attempt a racing start on the ice. La Plagne calls it the taxi-bob, but unlike most taxis it only takes you one place: downhill, fast. We climb in, me behind Jacques, with Martin, then Stephen at the back, and wait five minutes, filled with excitement and dread, until the control room says go.
Some unseen hand gives us a gentle shove and we start to slide. The scratch of metal runners on ice grows louder, and as the track walls narrow the phrase "staring down the barrel of a gun" pops into my head. Only, in this barrel, we are the bullet.
Within seconds we're feeling totally disorientated. The 3G-force on the big bends pushes down on our necks and chests, and it takes all our strength to hold our heads up. The speed with which we swing from perpendicular left through 180 degrees to the right is astonishing. Stephen, at the back, feels the judders most.
I know there's a long straight before the final hairpin, and when we come level I brace myself for that last bend. But it never comes. We are actually on the finishing straight, and though it still feels as if we're plunging downhill, we're climbing at 20 degrees to slow down. With a gentle crunch, Jacques brakes us to a halt. And, I realise, I take my first breath since setting off.
Jacques hops out like he's getting off a bike. I heave myself up and look round for the amigos. They, too, look shaken but through the slits in their helmets I can see their eyes shining. We've done it, in a flash.
Jacques is disappointed with his time, 1 minute 17 seconds, but is buoyed when he learns our maximum speed was 123kmh (76mph). German ace Manuel Machata has been only 2kmh faster in practice today. And if we'd done a running start, we'd have posted a perfectly respectable time.
We help load the bob on a flat-top truck to drive back to the start. It is the end of the afternoon, and a steady stream of tourists is arriving. They are here because La Plagne has come up with a brilliant way to help towards the track's running costs. Called the bob-raft, it's a fatter, foam-cushioned sled that runs on metal pads rather than blades. It needs no pilot but it's still no slouch, with a maximum speed of 80kmh (50mph), so you get the thrill of the run with less of the terror. La Plagne is part of the huge Paradiski area, and so far 15,000 visitors have taken the plunge.
We three amigos jump in to the first raft, casually now, knowing it will be a hay ride compared with our previous run. But why waste the fourth seat? We persuade Jacques to join us, and he climbs in at the back. At the last moment, he decides to turn round and go down backwards for "a different view of the track".
We're pushed off, and the bob-raft bumps round the first couple of bends until it gets into a rhythm. There is time to see the bends coming, notice where the starts for luge and skeleton races join the track lower down, and get another look at that calendar picture. It's fun and exhilarating, like a rollercoaster ride, the narrow ice walls intensifying the impression of speed.
We slide to a halt and wait for a second raft to come down before we pile into the truck. Among the second wave of rafters is a boy of about 12, grinning from ear to ear. I think back to my young self watching John Noakes on TV: how I would have loved that.
• The trip was provided by La Plagne (la-plagne.com). The Bob Experience costs €114pp for the taxi-bob (now renamed le bob-racing), €40pp for the bob-raft. Accommodation was provided by Terra Nova Hotel in Plagne Centre, which charges from €600 (£495) for six nights' half-board (hotels-altitude.com/fr/hotel-terra-nova-la-plagne-hiver.php)
