Caterham Supersport

Price: from £19,995

Engine capacity: 1.6-litre four-cylinder Ford Sigma

Power output (bhp@rpm): 140@6,900

Top speed (mph): 120

0-62mph (seconds): 4.9

It's got a four-point racing harness, a bright-red starter button and racing seats. It doesn't have air conditioning, power steering or even a radio, and you have to pay extra for a windscreen. This bonkers-looking machine is the Caterham Supersport and it's about as close as you can get on today's roads to Mr Toad's wind-in-your-hair sports car of The Wind in the Willows. And what better place to test the latest kit car from south London than at the Goodwood Festival of Speed? So last weekend I dug out my driving gloves and headed to Sussex.

The long, bendy lanes on the way south to Lord March's racetrack are the perfect place to test it. I set out early to dodge the traffic and the Supersport is in its element – it's designed with empty Sunday morning roads in mind. It's a lighter, more powerful version of the classic Caterham Seven (unless you pay a £2k premium, you have to build it yourself), which means it gets the same power-to-weight ratio as the Jaguar XK-R and it will get you to 60mpg in a very sprightly 4.9 seconds.

Hitting a long bend at 40mph would be dull in a Ferrari, but in the Caterham it's an electrifying experience and every mechanical element of the car is at work. This is real driving. And if you want to have some real fun, simply squeeze the throttle as much as you dare, flick the wheel and the back will come out with ease. It's not something you could do safely in a 700bhp supercar.

It's not for the faint-hearted, though – the wind batters you, driving rain can lash you painfully, there's a near-constant reek of petrol, and flying stones will really sting on unprotected flesh – but as the engine warbles, then rises in tone, you know you are in a proper driver's car. You need to work the wheel and pedal hard to get what you want but in return it's a joy to throw around.

Later in the weekend I have to pop around the M25 for a family do. The motorway isn't its natural home and there are several hairy moments with lorries. Putting the roof on means you'll be deafened and then slowly cooked by the exhaust. And getting out after a long journey is likely to break your back worse than the effort of climbing in.

Men (and women) of a certain age will love this car, though – I spent the afternoon blitzing up and down country lanes as each member of my extended family clamoured for a go. Its shape reminded them of their old Austin-Healey frog-eyed Sprites, while its retro switches and toggles took them back to a happier, Bakerlite-tinted age. Best of all, you don't even need to build one yourself. Caterham now hires out the slightly less powerful Roadsport version for the day (£175). And if you go on to buy one, it will take that off the retail price. For a slice of true motoring pleasure, I can't say fairer than that.