There are two things you should never do on a rainy day: drive a car with no roof, and drive one that’s never turned a wheel in the wet. If you are foolish enough to ignore such simple advice, however, then why not go the whole hog and take a lightweight 155mph sports car on its inaugural wet-weather test on a rain-soaked racing circuit? While you’re at it, make sure the car in question is a prototype rather than a production model.

Yes, welcome to the Goodwood Motor Racing Circuit, West Sussex, and my ride for the day — the Javan R1 (pronounced Jay-vn) which, before I got behind the wheel, had barely covered 1,000 miles. Javan Sports Cars is one of those small British companies you’ve probably never heard of that builds super-fast, super-light sports cars on a shoestring. What it lacks in financial muscle it makes up for with the passion and know-how of its designers and engineers.

Based in Helston, Cornwall, it is run by Andrew Fletcher, 37, and Javan Smith, 63, who lent the company his name. It is such a small firm that I unwittingly became its chief test driver.

The R1 has been touted by some as a rival to the Lotus Elise. For £30,139 you get an open-topped sports car that can reach 62mph from standstill in 3.6sec — 1.3sec faster than the Elise R. There are no luxuries, no doors even, but Javan is promising a power-to-weight ratio more impressive than that of a Ferrari, and the chance to join an exclusive club of Javan enthusiasts. It claims that several left-hand-drive versions have already been ordered from America.

Fletcher and Smith used to build model cars and planes before launching their company in 2002. Nothing wrong with that, but when you are about to floor the throttle on a real-life racer it’s nice to think you have the depth of experience of, say, BMW behind you. Or even Caterham. And the pretest briefing was anything but reassuring: “Golly, I’m just thinking of all the nuts and bolts I’ve put on it,” says Fletcher as I take the keys to the R1. “Hope they’re okay.” And so do I.

The Javan’s striking appearance may seem familiar. It was originally badged Strathcarron and powered by a motorbike engine with no reverse gear. Javan bought the body moulds when Strathcarron went bust in 2001, and fitted it with a Honda engine and gearbox. If the R1 had been launched a decade ago when such models were thin on the ground, sports car fans might well have given it a hero’s welcome. But nowadays it seems as if there’s a new one out every week — which is great for you and me, but not so good for Javan.

For example, you can now buy an Elise or Caterham Seven, with proven power, strong dealer support and such creature comforts as doors and a roof for £6,000 less than the Javan. But Fletcher doesn’t see either of these cars as a competitor to the R1, and instead has his sights set on the Ariel Atom. “The R1 is more comfortable and you don’t need to wear a helmet,” assures Fletcher, which is like saying that if you tread in dog mess you’re better off wearing sandals than being barefoot. True, but only just.

So who would spend more than the national average annual wage on a car that was a flop the first time around, and that’s now built in a shed by two former model-maker pasty eaters?

“Our customer profile is likely to be 35 to 55-year-olds who already have one or two cars and who’ll use the Javan as a plaything,” suggests Fletcher. “One potential buyer told us he wished he’d bought one instead of blowing £30,000 in depreciation on an Aston Martin DB9.”

The R1 is certainly a very light car. Thanks to a honeycomb aluminium monocoque it weighs just 670kg, giving it a power-to-weight ratio of 330bhp per tonne, which is more impressive than a Ferrari 430 Spider at 322bhp per tonne. What’s more, with its rev-happy 220bhp Honda i-VTEC engine it’ll romp to 100mph in 9.8sec, accompanied by a fruity soundtrack from a stainless-steel exhaust with twin tailpipes.

With only 12 R1s being built per year, Fletcher believes Javan owners will be “buying into an exclusive club — a little community that will share feedback”.

They’ll need to. May I suggest the first topic for discussion should be how to step into the doorless R1 without leaving a muddy footprint on the seat. They should then organise a conference call about the handling. On the Goodwood racetrack in wet conditions the R1 was skittish at the best of times and gave me the closest sensation possible to flying without actually being in a plane. Instead of feeling well planted and secure, as 100mph came and went the R1 mimicked the mating dance of a frenzied fly, doing a poor job of finding grip through the surface water. This wasn’t helped by 17in wheels shod in nonmatching rubber, and I hadn’t even heard of the tyre company covering the rears; Vietnamese I think.

I soldiered on, squeezing the brake pedal much earlier than is usually necessary on the way into the corners. I wasn’t even sure I’d be able to steer myself out of trouble: between my hands the Javan’s wheel turned with a slightly sticky feel.

The fact that this sports car arrived at the Goodwood circuit with its set-up better suited to road rather than race use (softer suspension and lower tyre pressures) is a poor excuse for unnerving handling. To be fair, Fletcher and his partner claim they have since overhauled the steering in response to my “constructive criticism”, not to mention my deathly complexion as I removed my helmet. “We shortened the steering arms by 12mm and the car is totally transformed, with the added bonus of a tighter turning circle,” says Smith. But after my last experience, I’m not inclined to verify his claims.

And so to the road test. Having removed my helmet-cum-umbrella, I went in search of West Sussex’s finest potholes. I’d found enough within the first two miles to shake a nut loose from the windscreen-wiper mechanism and render it useless. And there I was thinking the day could only get better.

The Javan’s straight-line acceleration proved its best feature on the track, but a more cautious right foot was required when mixing with the public. With the rain still pouring, I could have also done with some wellies — and that is hardly what open-top motoring should be about. But that’s the killer problem with this car.

I love the fact that this country produces so many plucky little companies and entrepreneurs willing to indulge their passion for motors by building their very own. It is a cottage industry of which we should be proud, and I wish Javan the best of luck — especially now that the teething problems I encountered have been ironed out. But the cars they make must be as good to drive as they are to look at.

Waiting at the lights with rainwater streaming down my neck, mascara running down my cheeks and dreading the next pothole or sharp bend, I noticed people stopping to stare. The R1 is undoubtedly a rare-looking beast, but unlike the head-turning Elise I’m afraid it doesn’t make you feel at all sexy behind the wheel.

Jeremy Clarkson is away

Vital statistics

Model Javan R1

Engine 1998cc, four cylinders

Power 220bhp @ 6800rpm

Torque 155 lb ft @ 7000rpm

Transmission Six-speed manual

Fuel n/a

CO2 n/a

Acceleration 0-62mph: 3.6sec

Top speed 155mph

Price £30,139

Rating 2/5

Verdict Slippery when wet

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