Mini Cooper SD Roadster

Minis always felt like nippy motors – but can they really be sports cars?

Firm favourite: The new Mini Cooper SD Roadster

Price: £21,630 (range from £18,020)
Engine: 1,995cc, four cylinders, 16 valves, turbodiesel, 143bhp
Transmission: Six-speed gearbox, front-wheel drive
Performance: 132mph, 0-62 in 8.1sec, 62.8mpg, CO2 118g/km

The Sun might be a familiar sight now, but it was pelting it down as I drove my 1959 Mini – whose engine started to splutter and hiccup just as old Mini engines used to do when drowning – to the launch of the new Mini Roadster. All that rain was not ideal for test-driving an open-top, but it would be a good measure of the roof's water resistance, and speed of opening when the weather let up.

But before that, there's one question that hung over this launch: isn't there a Mini Convertible already? What is the point of another soft-top Mini?

Several points, actually. It gives those who have already owned Minis the chance to buy a different one. It fits nicely with the recently launched Mini Coupé, which is the same car apart from the roof arrangement. And it allows the Mini marketing people to describe their new two-seater as a Mini sports car, the sort of car that might appeal to those who otherwise might consider an Audi TT Roadster or, more likely, a Mazda MX-5.

There's an irony here, because one of the most amusing things about an original Mini was that it was not a sports car, yet it could do sports-car things – nip round corners, squirt through traffic, race on racetracks, make its driver smile – better than most sports cars. So it beat them – and now it's joining them.

And why not? At the more affordable end of the market, the front-engine, rear-wheel drive template that was once the sports-car norm is practically history nowadays. So there's no reason why a compact two-seater shouldn't have front-wheel drive and a transverse engine.

With just two seats, the Roadster has a big boot and a useful space behind the seats. Roof up, it looks less contrived than the Coupé thanks to its simple fabric top, whose operation is electrically powered but requires you to release or lock a single clamp above the interior mirror to start or finish the process. Opening and closing take just eight seconds, and can be done at up to 20mph; when stowed, the roof sits flush with the rear deck, with just the flat front part neatly on view. Nor does it leak or cause wind noises when closed.

It's snug in the cabin but never claustrophobic. As in the Coupé, the windscreen leans further back than in a regular Mini to give a racier profile, but it doesn't intrude on your space. And here's the key advantage over the existing Mini Convertible: with no rear seat, there can be a bracing bar across the cabin, which makes the structure much stiffer.

You can feel this within seconds of driving off, because there is hardly any body shake over bumps. This open Mini feels as all-of-a-piece as solid-roofed ones. It's heavier than they are, weighing around 1,200kg, but with the right engine it still sprints with verve.

That engine is probably not the 122bhp 1.6, which might struggle with the weight, but the Cooper S (164bhp, 1.6 turbo) and Cooper SD (143bhp, 2.0 turbodiesel) do the job very well. There's also the 211bhp John Cooper Works version of the S, which would prove very rapid, but the regular S and SD I tried seem lively enough.

Outright pace is greater in the S, but I favoured the SD for its effortless overtaking energy – and the fact that it will cover real roads just as quickly while using significantly less fuel. Both cars cope well with bumps, being more softly sprung than solid-roofed fast Minis, and that greater suppleness also makes the steering feel natural. Yes, I do believe the Roadster SD is my favourite Mini. Apart from my 1959 model, of course.