Oh, mate. I had no idea. I had read about the Rocket, of course – the tiny sports car designed by Gordon Murray and made by the Light Car Company in the early 1990s.

When it was new and I was a skinny teenager, I would have devoured every word and remembered every statistic from Autocar’s Rocket review and performance test.

And some numbers just stick, no? You will never need to look them up again. You will forever know that the Jaguar XJ220 did 217mph and the McLaren F1 made 627bhp. So when I accepted the generous offer from a reader to have a drive in his Rocket last week, and as we stood looking at it, I said: “385 kilos, isn’t it?”

“That’s what [LCC founder] Chris Craft told me,” replied the owner, “and he was a pretty straight guy.” I’ve since been back to check Autocar’s test. The Rocket tipped our scales at 400kg carrying more than 20 litres of petrol, so Craft’s 385kg claim would have been spot on.

Which makes the Rocket the lightest road car I’ve driven on the road. Presumably a Sinclair C5 doesn’t count. I have driven (very few) lighter cars with engines and numberplates – Austin Seven specials – but only on a circuit. These 750 Motor Club racers tend to be in the low-300s. Murray once designed one (for racing only) at just 280kg.

The short of it, though, is that if you like lightweight road cars, the Rocket is about as good as it gets. I’ve written about how motorcycle-engined cars can frustrate, because, congrats, you’ve reduced the engine size but now the car is too big. The Rocket was designed small to fit a Yamaha FZR1000 engine, making 143bhp and revving to 11,500rpm.

Among a few modifications, this particular car has had its passenger seat (as standard located behind the driver) deleted and the fuel tank moved there, from above and behind the engine.

The seat is a Tillett kart-type one, fabric not vinyl and leather, so as grippy and supportive as in a good kart. It rides on lighter wheels too.

There are four-point harnesses and a generous degree of shoulder room within the spaceframe chassis. The throttle and brake are to the right of the steering column, the clutch is to the left. The diddy gearlever sprouts from between chassis tubes and it’s only a few centimetres from the round steering wheel.

What’s it like? A total dreamboat. The clutch is a little (but not too) sharp, but stalling is always a possibility for clumsies like me. The control weights are all light and delicate – exceptionally so.

The steering lock is poor but the steering ratio is right and the front is so little loaded that you can steer with your fingertips.

The gearshift is a five-speed sequential, and you can make clutchless upshifts by just easing a bit of finger weight against the lever, then lifting the throttle slightly to ease shifts through.

There’s a transaxle with low and high ratios and to provide reverse ratios, so actually there are 10 forward and five reverse speeds, but in practice you tend to use the lower five forward ones (and one reverse). It’s not like it’s too short-geared in the low ratios: the redline in second is above 90mph.

That means the ability to be in its zone is limited, because peak torque is only 77lb ft at 8500rpm. But because it weighs so little and because there’s only so fast you can go on the road anyway, you can make brilliant progress through its fizzy mid-range, making really small, low-effort control inputs.

No car is like a motorcycle but, because the Rocket is only 1.5m wide, because the control weights are so precise and easy and because it’s so responsive, you can brake with a flex of the toe. I found driving it had a similar flow and ease to riding. It makes everything else feel big.

A Range Rover? Fatso. Alpine A110? Bloater. A Caterham Seven? You should cut down on your porklife, mate, get some exercise. Sub-400kg is where it’s at.

I thought the Rocket would be good. What I didn’t expect is that it would enter my ‘favourite road cars of all time list’ somewhere in the top one. What a thing.