The basic premise is this: you're perched on top of a 1,000cc engine (and not very much else) behind a leather-clad nutcase who makes a living riding two-wheelers very, very fast. He's got five minutes to introduce you to his white-knuckle world, and has been instructed to scare you silly. Anyone of a nervous disposition simply doesn't stand a chance.
My pilot is called James Haydon, he's 30 years old, competes with the Rizla Suzuki team, and boasts a list of medical complaints like a junior doctor's training manual. In recent years, Haydon has broke his ankle, his left wrist twice, right wrist three times, collar-bone, thumb, fingers twice, knuckle (ouch!) and several ribs. Now my life is to be placed in his patched-up hands, on the lethal bends of Castle Combe. If that wasn't terrifying enough, we've arrived in the pit-lane in time to see an over-zealous rider being bought home in the back of an ambulance.
But surviving a superbike journey requires little in the way of technical ability. The passenger's job is to wrap arms around the driver's waist (in the manliest fashion possible), and behave like a sack of spuds. Sudden movements are discouraged, since they upset the delicate balance of these machines, with obvious and unthinkable consequences.
Whoosh! Down goes Haydon's right wrist, off goes the Suzuki, and I'm rocked back in the saddle like someone's smacked me in the face. They weren't joking when they said it'd be quick: heading down the straight, I open my eyes for the first time, only for a gust of wind to nearly take my head off. I'm terrified, and we haven't even reached the first bend.
It doesn't take long arriving, though. Half a second after hitting top speed (around 160mph, since you ask), we're back at a sedate 80 for the first of Castle Combe's many sharp right-handers. Braking at this sort of speed throws my backside clear of my seat and near-as-dammit over the handlebars. Coming round each corner, our knees graze concrete. We're leaning at an absurd angle and every moment I expect this fragile relationship with terra firma to come to a messy end. Finally, as we accelerate into each straight Haydon pulls a wheelie and I'm on the verge of being reunited with lunch.
Haydon competes in the British Superbike championship, a thrilling two-wheeled version of touring cars. When he and his chums aren't terrifying journalists, they travel the UK competing on largely the sort of machines that you or I could buy from a normal garage. Their souped-up versions do battle at 13 different meetings across the country each summer.
Organisers claim their sport is said to be undergoing something of a renaissance - grotty Hell's Angels being replaced by respectable middle-class types and that kind of guff - and tattoos and beards were certainly outnumbered, when I visited earlier in the year, by deckchairs and picnic hampers. The racing itself is decidedly edgy. In contrast to Formula One, or other sterile, tactical, car races, motorcycles still overtake each other. Mistakes get made, and, since it is raining, messy accidents abound.
At the sharp end of Castle Combe, it takes a couple of two-minute laps for my brain to believe that I might survive this hair-raising interlude to daily life. Soon I start to enjoy myself, and to feel a certain affinity with the macho professionals I had witnessed breathlessly some weeks previously.
As we reach the finish, I throw off my helmet, with a smile as wide as a chequered flag, and thank Haydon for giving the machine such a testing ride. And then reality bites: he quietly admits to have "only given it about 65 per cent of full poke". In a race he'll crank it up to 180mph and throw the machine around "properly". Now that really would have reunited me with lunch.