For how long now has the Caterham Seven been the definitive lightweight sports car? From Ginetta to Zenos, all have had to face the Seven as their benchmark, almost regardless of remit, powertrain or price. If it's light and it's British and it goes really fast, there will be some kind of Caterham to take it on.
Challenges to its greatness have rarely been as serious as this, though. The Ariel Atom has been so comprehensively overhauled for its fourth generation that keeping the same name almost seems to do it a disservice. While the look is familiarly bonkers, just two pedals and the filler cap are carried over - everything else is brand new. With nearly two decades and three generations of Atom building experience behind it, Ariel is understandably proud (and optimistic) about what it has created here. First impressions have been positive, extremely positive in fact, but the Seven hasn't been the de facto choice in this sector for so long for no reason. To unseat it the Atom will need tosurpass the wildest, lairiest, most powerful Caterham there is: the 620S.
That seems far too prosaic a name for a car with nearly four times the power of an entry level Seven - 'Destroyer' seems more appropriate, especially in this colour - but that's what we have. Can a turbocharged engine really match a supercharged equivalent of the same capacity? Will the Atom's additional width count against it on tight, demanding roads? How forgiving can a mid-engined car be against a famously approachable front-engined adversary? And will it ever stop bloody raining?
Yes, as you can probably tell, the weather could hardly have been less suited to these sorts of cars. On the A303, at Crewkerne, at Cheddar Gorge and seemingly everywhere in the south west, on the day we're shooting the weather is just appalling. There's no escaping it. We discuss postponing the shoot with Ariel, to spare both the car and the blushes of the plonker about to drive it. But Ben is on the way in a Caterham, and Luc is en route to photograph - the shoot has to go ahead. Tom from Ariel finds some waterproof trousers. He also explains the new dash layout, up to and including a TC dial that isn't yet wired up. Because it's pre-production. And he thought packing spare pants was a joke...
But it's all going to be fine, right, because the car puts you immediately at ease? Er, not exactly. Having never driven an Atom before, there's some trepidation around 320hp, 595kg, Avon ZZRs and not a single driver aid in this weather. Plus the associated distractions of being in an Atom, like watching all the incredible componentry do its respective jobs - best done as a passenger, that one. Truth told, this is where the lower power settings are welcome, delivering less boost, less noise and less savage performance. Ease yourself in gently, right? Rest assured just over 200hp and less than 600kg feels plenty brisk, thanks very much.
Soon enough though, despite not really being able to see, the incessant blasting of wind and the piercing cold, it all starts to make sense: this car is good. Really, really good. Nobody has died. This might almost be enjoyable. Oh wow, these gears are short if the shift lights are on already. Ah, that's wheelspin. Again.
Wound up to the full 320hp, the Atom 4's motor makes it terrifyingly fast, even at about 30 per cent throttle. The Civic Type R from whence it came delivers good throttle response and relatively little sense of turbo'd inertia (as well as being really quick), so the impression when it's propelling a car 800kg skinnier, as you can probably imagine, is one of near-immediate, unrelenting and really quite violent speed. It's insane. The Atom sounds like Darth Vader's Dyson too, whooshing and wheezing in response to every throttle application. Which is fun. But it says much of the Atom's manifest ability that this is a car capable of 0-100mph in six-point-something seconds, and yet it's not the performance that's the most memorable aspect.
Alright, that's a bit of a lie. The power is not the most memorable aspect of driving until the Atom wheelspins in fifth gear - then it is. Knew the pants were wise. Up until then it's a chassis and dynamic set up of such exquisite quality that shine brightest on a truly miserable day.
The steering is fabulous; measured, accurate and brimming with feeling, but without the kickback often associated with unassisted set ups. It's no exaggeration to say it's the best steering on any car today. The ride, alexquisite, deft in its control and endlessly compliant, making the Atom seem so much less skittish than you might expect. Beyond a bit of squidge right at the top of the pedal the brakes are stupendously good as well, immensely powerful but also very easy to modulate. Even in Somerset's monsoon season, ABS isn't missed. Finally, despite a user-induced scare, grip and traction are actually spookily good, all things considered. There's real, tangible quality to the Atom's driving experience; it isn't simply about overexposure to the elements and the white knuckle effect of too much power - there's joy to be had just interacting with it before you even get to the business of exploring its almighty potential.
When Ben arrives though, smug in the Seven, it's hard not to feel a tiny bit jealous. He has heated seats, after all. And a roof, of sorts. And, luxury of luxuries, a windscreen - the decadent sod. There's no escaping the fact, however, that the Caterham looks like what it is - which is quite old. It's almost dainty in the Atom's company, impossibly narrow and somewhat quaint against the mid-engined, modernistic Ariel.
Time to drive it. Or rather, get in it. Even with the roof off, getting comfy in an S3 is not the work of a moment, battling with the harnesses and desperately seeking more room. Quite frankly it's desperately cramped, intimate to the point of being uncomfortable. The dashboard is like Boggle for switchgear, making even less sense than usual jumping from the Atom, the ignition barrel is still fiddly and it simply doesn't feel as well built as the Atom does. Of course these things are about the drive above all else, but they are still £50k play things - you want them to feel worth it.
Has an Ariel Atom ever been the sensible, measured, mature option in a twin test? Probably not - but it is now. Because, to be blunt, in the wet, the supercharged Seven is an absolute bloody lunatic - completely, utterly berserk. Attempt the same sort of throttle applications as in the Atom and those tiny 13-inch wheels will be overspeeding immediately; it may use less focused Avon ZZS tyres than the Atom, but they're also just 215-section at the rear - the Ariel's ZZRs are 255-section, plus it has the natural traction benefits of its engine location.
Of course, once your aware of the fact that the 620S wants to do this pretty much everywhere, it's an absolute joy. It seems infinitely adjustable, playful and transparent on the throttle, perhaps more than any other Seven because there's such a surfeit of torque to manipulate the balance with. Being so narrow may mean the driver doesn't really fit, but it opens up the road significantly, and quite naughty slip angles can be indulged in the safety of your own lane. The powertrain, despite the best efforts of the Ariel, is the more exhilarating and satisfying here as well; the throttle response is more urgent, the sound more musical and the top end intensity - when you dare - just downright thrilling. Ally it to an even shorter, sharper shift than the very good one in an Atom and the Seven drivetrain is ecstasy.
Everything is so immediate and so raw, even against Somerset's finest. Throttle, steering, gearshift, the loss of grip and the way it comes back; there's no delay. Ever. You'll need to bring your A-game, because really this is more engine than a Caterham ever needed, but the rewards are commensurate - it's utterly wild, and completely lovable.
There's no escaping the fact, however, that the Atom 4 reveals flaws in the Seven. The more rudimentary suspension makes the latter less composed and more easily flustered in terms of wheel travel, which is not exactly ideal in these conditions. The brakes aren't as powerful, and the pedal feel is less reassuring (though bear in mind the discs that can be fitted behind 13-inch wheels, against 16- and 17-inch ones). In addition it's not like the Atom's higher limits are at the expense of playfulness - beat the traction and there's mid-engined balance and poise to spare, seemingly without the spikiness associated with the layout. (Well, it didn't spin with the weather like this, so that's encouraging.)
Put simply, beyond that shrieking supercharged Duratec, there's nothing that the Seven does that the Atom can't comfortably match or, in most cases, surpass. Of course you would hope that a four-year, ground up redesign would see it triumph over the old stager, but the difference is marked.
By being a more accomplished and more rounded driving experience, it feels like there's more to learn and explore in an Atom than there would be in the Seven. Truthfully this is not Caterham at its most compelling, the architecture probably overawed (in a hilariously entertaining way) by more than 300hp rather than really designed for it - a non-supercharged 2.0-litre is more likeable. And sane. The Atom, on the other hand, feels designed for 320hp because it, er, was designed for 320hp.
The end result, therefore, is that the Atom is more intriguing as a static object, has greater depth as a driver's car, feels of higher quality and costs less money. Caterhams are fabulous things - success is not enjoyed for this long with a mediocre product - but the concept's weaknesses are laid bare in this company. There should be no shame in coming runner up though, as the Ariel Atom 4 is not simply the best car in this test - it's one of the best cars of this year.
SPECIFICATION - ARIEL ATOM 4
Engine: 1,996cc, turbocharged four-cyl
Transmission: 6-speed manual, rear-wheel drive
Power (hp): 320@6,500rpm
Torque (lb ft): 310@3,000rpm
Top speed: 162mph
MPG: 30 (est)
Price: from £39,950
CATERHAM SEVEN 620S
Engine: 1,999cc, supercharged four-cyl
Transmission: 5-speed manual, rear-wheel drive
Power (hp): 314@7,700rpm
Torque (lb ft): 219@7,350rpm
Top speed: 145mph
Price: from £46,410