And if you think we’ve gone mad, let me reassure you that an unhealthy amount of processed pig is not the only thing in there. We also have a Teasmade, a gazebo and a portable loo. These are stacked on top of jerrycans and bottles of oil and a full set of alloy wheels and tires. To be honest, we were only supposed to transport the tires. But then I accidentally ordered a massive trailer, so I thought we might as well top up with other stuff. Spam. It’ll be useful at lunchtime.

You might reasonably ask what the hell’s going on here. So allow me to explain. The Atom is a road-legal racer you can drive to the track, race, then drive home again. But as it turns out, you need lots of stuff to go racing. Things like spare tires and spanners and Teasmades. Unfortunately, the Atom has less storage space than a pencil case. Some race teams would solve this by spending millions on lorries and motorhomes, but that’s not the TG way. Why would you trailer the car when the car could trailer your stuff? So when we received our invitation to race in the Atom Cup at Castle Combe circuit, there was only one thing for it…

Which is why we’ve just hooked up our Atom to 450kg of Brian James CarGo (see what they did there?) Shifter, complete with side fences so things don’t fall off. Coupling all this to a 570kg Ariel Atom is not only preposterous, but also technically challenging. Flyweight track cars don’t come with towbars, so we’ve had to fashion one onto the naked chassis using nothing but welding torches and raw hope. And after some sweating and pinched fingers, we’re all hitched. Everything we need to go racing, right here, including the car. Genius, eh?

And so here I am, strapped into the Atom in the Top Gear garage. I glance over my left shoulder, and my entire vision is filled with the CarGo, looming large like a large loomy thing. As I release the clutch, I feel the trailer drag slightly, like a reluctant dog on the end of a lead. And as I pull away, it feels like the Atom’s tethered to a bungee. Never has this famously skinny machine felt so immensely heavy. As I gently accelerate, it feels like the nose should be packed with ballast to stop it raising like the bow of a speedboat. I’m not driving. I’m floating. Maybe not so genius after all.

When you’re up and running, and provided the road isn’t dented or curved, the articulated Atom mostly behaves itself. But admittedly it’s not perfect. On the roads around Castle Combe, I hit a few bumps, and the whole set-up threatens to jackknife. And it starts to rain, which makes the front wheels skitter over the surface. This isn’t fun. But then, with history’s most unlikely accident averted, I spot a brown road sign: “Competitor Entrance 100 Yards”. Phew. So I peel off the road, thread my rig through the paddock and find a place to unload my lunch. With all that trucking, I’ve worked up quite an appetite.

Turns out the Atom Cup has a fine hospitality unit with platters of smoked salmon and a whole bar of delicious drinks. But while the other drivers nibble their vol-au-vents, I hack off a lump of Spam and sit on the ground. Castle Combe. This is not a place to be taken lightly – a throwback to days when the only thing hairier than the drivers were the tracks. As one instructor helpfully puts it, it’s the most dangerous circuit in the UK. Run-off areas are merely strips of grass. Beyond those, you’ll be greeted by earth banks or crash barriers, both of which should stop you exploring the surrounding woodland at speed.

Still, time for qualifying. Now, I’ve done a spot of racing before, but mostly in older cars at a gentlemanly pace. And usually on smooth circuits such as Silverstone, with their vast run-off areas. Not in razor-sharp Atoms on a track with many lumps and nowhere to hide. At some points, the bumps are so severe that my feet jump around, and it’s hard to line them up with the pedals. The pit of my stomach jumps up and whacks my diaphragm. The only option is to pin my right foot to the throttle and keep it there for a worryingly long time. If I had more guts, it’d stay there for longer, but the sensible part of my brain tells me to lift off sharply. Think of the return journey, Piers…

There’s no flattering way to put this: I qualify third from last. The race is just two hours away, which gives me time to invent some excuses and fiddle with the Atom’s set-up. Nothing major, but we’ve gone slightly softer on the dampers and given the front brakes more say in proceedings, which should encourage the nose to find an apex with more confidence. I say “we”, because all this is done by the mechanics that come as part of the service for the Atom Cup. Costs vary depending on the level of attention you want, but different packages are available from £50,000 to £60,000. That includes the cost of the car, 16 races over eight weekends, and even the most basic investment gets the full hospitality treatment, which includes catering from the same people who do the food for the McLaren F1 team. It’s mercifully Spamless.

Better to have a light lunch, I say – it’ll help the power-to-weight ratio. And as I line up for race number one, I need all the help I can get. It’s a standing start, and, given how things have gone so far, it’s no surprise that I fluff it. My initial reactions are OK, but I hit the limiter in first, and the only two people I out-qualified are immediately threatening to come past. I don’t know the other racers at all, but I spotted a couple in the paddock with some meaty-looking fists. And I’m not sure how much they use their mirrors. If I go for that gap, will they know I’m there? If not, will I taste those fists? So I hang back, hoping one of them makes a mistake.

They don’t. So I pass some time by analysing my lap times. I know these to the millisecond, because the Atom is fitted with a data logger, which displays not only your lap time but also sector times. It doesn’t hesitate to tell you when you’re slower in one particular place or another. Or that blue isn’t your colour and that stripes make you look fat. Looking at all this on the digital dash is like having a personal trainer constantly bawling right in your face. Unfortunately, the encouragement is lost on me, and I finish one place worse than I started. Second to last.

For race two, the late afternoon sky is heavier than a wet towel. It’s raining over half the circuit, but I’m using dryweather tires. This should be interesting, especially as I’m lining up second to last on the grid. And sure enough, in some places, grip is nothing but a distant concept. And to make matters worse, I’ve lost my rhythm. Sometimes, I understeer; other times, I oversteer. Sometimes, I don’t steer at all. I’m in last place, and it looks like it’s the wooden spoon for me until, finally, I try a lunge down the inside into the final corner.

Through a blend of bravery and good luck, I complete the move, and there’s a ripple of applause in my head as I cross the finishing line. From what I can tell, the car is undamaged, so I won’t be hiring donkeys to get the trailer home. Back in the paddock, I back the Atom up to the CarGo and re-hitch. The load will be a little lighter on the way home, and so will the one that weighed upon my shoulders. As I change into my clammy waterproofs in preparation for the moist drive to London, a few of the other drivers go past in their big saloons and posh SUVs. I don’t receive a single jealous glance. Gentleman drivers? Hmm. Let them eat Spam.

This story originally appeared in the October 2013 issue of Top Gear magazine.