Our Caterham Seven is quick, but there's one thing that takes it to a new level...

This might be one of the most special driving memories I’ll ever have below 40mph. It’s a golden-skies evening at Donington Park circuit. I’m driving the evo25 Seven, roof off. Just ahead of us is Caterham CEO Bob Laishley, in a Seven 420 Cup. Just to my right is ‘LegoCat’, the wild, bright yellow 620R on which Lego’s Caterham kit series was based.

And behind all of us, bathed in the setting sun as we roll to a halt at the finishing line to conclude a special parade lap, is a never-ending conga line of roughly 400 other Sevens, celebrating 50 years of the Caterham Seven – and, in our car’s case, 25 years of evo.

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We’re at Donington Park for two reasons: one, to join in Caterham’s birthday celebrations (music, displays, hundreds of Sevens from every decade and a Sevens-only trackday in which we’ll be taking part in the evo25 car), and two, to meet our car’s racing cousin. Because the other element of Caterham’s birthday bash is racing. The company’s full range of championships will run throughout the weekend, from the absolute-beginners Academy series all the way up its racing ladder to the flagship Caterham Seven Championship UK: slick tyres, a sequential gearbox and seriously quick lap times. Terrifyingly, this weekend there’ll be another entrant on the grid: us. Or more specifically, me, hoping that the miles I’ve logged in the evo25 car on road and track will serve as homework for joining one of the most famously feisty one-make championships in the UK.

There really is a huge amount in common between our car and the UK Championship race car (the black and red car pictured here). They share, barring a few tiny detail differences, essentially the same engine: a 2-litre Ford Duratec-based unit in Caterham’s 420R tune. Essentially the same dampers, too, only they’re adjustable in our road car and fixed by regulations for the race car. The racer has a beefier roll-cage than our car’s road/track hybrid one, necessitating getting in through the roof. And in place of the five-speed manual H-pattern in our car, there’s a race-spec Sadev sequential gearbox.

You’re nestled low in the car, harnessed in and your wrists tethered to the harnesses by a short-ish strap too (intimidatingly, to stop an arm being flung outside of the car by the forces in a crash). Ahead of you, a race-spec digital display and the world’s widest central mirror, to give advance warning of incoming divebomb outbraking moves.

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It’s one of the most fun vehicles of any description I’ve ever driven. The clutch is light, easy; it’s no more difficult to drive around the pitlane and paddock than the road car. Gearchanges are flat on the way up: don’t lift from the throttle, just give the sequential lever a strong, positive pull and it automatically cuts the ignition for a flat upshift. You do need the clutch on the way down, and a blip on the throttle to match the revs – if you can find the time. You’re not on the brakes for very long.

The grip the featherweight Seven generates on sticky slick tyres is enormous. Down the Craner Curves (taken flat in these cars) I feel like my head’s going to be pulled from my shoulders. We screw the headrest support (a foam-padded metal plate) out a bit further for the next session so I can push my head back into it and relieve some of the effort. The other thing that’s become clear is that a tow is crucial; with the Seven being such a draggy open-wheeled shape, the slipstream effect you get from other cars is like nothing else I’ve experienced. In qualifying, a tow can make the difference between a slow time and a competitive one.

All of the drivers are well aware of this, ducking into the pitlane if they sense a driver’s tucked into their slipstream during qualifying, while being savvy enough to find a car of their own to follow. I only manage to find one lap in another car’s tow in the entire session, and line up 15th out of 20 cars. Racing a Seven is clearly a specialised art, and Caterham subdivides the championship table into two classes: Pro for seasoned drivers and Am for those with less Seven-specific experience. I’m in the Am class, along with ten other drivers.

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The three races that ensue are the most intense I’ve ever experienced. The slipstream effect means the field never really spreads out, and with the ability to run side by side more easily than in other racing cars, overtaking moves take two or three corners to complete. Racing is almost impossibly close, inches apart – or less at times. Although for fleeting moments I get into the top ten and run third in the Am class at one point, it’s not long before I’m shuffled down the field; make one mistake, or lose one position, and you’re quickly swallowed by the pack. In the first race I end up right at the back; in the next two I sharpen my elbows a little more and finish 15th and 14th after some of the most breathlessly exciting driving I’ve ever encountered.

Driving the evo25 car on track in Caterham’s Sevens-only trackday the next day I expected it to feel like a comedown after the slick-shod, sequential-geared racer. Yet it really was much, much closer than I expected, both in terms of excitement and pace. The shared DNA with the 420 race car is real and tangible, and makes the evo25 enormous fun.

This story was first featured in evo issue 317.