Mighty Midget sets the pulse racing

Based on a lengthened version of the Smart City Coupé platform, and powered by an uprated version of its three-cylinder engine, the newcomer - on paper - doesn't sound as though it's a thriller. Nor do the performance figures of 0-60mph in 11.2 seconds and a top speed of 105mph give the impression of a true sports car.

But the Smart Roadster is more than the sum of its parts - and that's apparent as soon as you climb behind the wheel. Not only is it surprisingly spacious inside, but it's also incredibly funky. It needs to be, as this vehicle will be competing in a new but very competitive sector when it arrives.

Recalling budget two-seaters of old, such as the Austin-Healey Sprite, MG Midget and Triumph Spitfire, the Smart will do battle with exciting new models including the Ford Streetka, VW Polo Spyder and Vauxhall's Tigra replacement, which will also come as a cabrio.

But while its rivals promise to be somewhat restrained inside - especially the Streetka, which has lost most of its vibrant concept interior - the Roadster's image will remain in keeping with its distinctive and colourful City Coupé stablemate. The bright fabric-covered dashboard features traditional Smart cues, such as a chunky plastic steering wheel and push-pull gear selector, while clever touches include a passenger seat which can be folded to form a table with a drinks-holder when travelling solo. Sporty additions include a large chrome-edged speedo and pod-mounted rev counter.

However, the real pleasure is in the driving. Although it shares an amazing 35 per cent of its components with its microcar sibling (including brakes, suspension and steering parts), the Roadster has been given an entirely different character. Fire up the three-cylinder 698cc engine. and it chatters like only a three-pot motor can - responding to the throttle with a raucous snarl that could easily be mistaken for a unit with twice the number of pistons. There's more than a hint of Porsche Boxster about the soundtrack - and the noise isn't the only similarity between the two German machines.

As with the Boxster, the Smart's Suprex turbo-charged engine sits behind the passenger area and, also similar to the Porsche, positioning the powerplant here gives the Roadster near-perfect weight distribution, but biased slightly to the rear. That translates to a vivacious driving experience which means corners can be attacked with real vigour. What's more, the throttle is infinitely more communicative than that of the City Coupé, so the rear-wheel-drive Roadster provides instant responses and can be easily balanced. Despite modest acceleration, it makes the car feel incredibly fast.

The newcomer isn't without its faults, though. The 'Softip' transmission is quicker than that found in standard Smarts, but it still lacks the eagerness and control of a manual gearbox, while the brakes need more feel and fade quickly if used too enthusiastically.

Two bodystyles will be available when the little two-seater goes on sale in July next year. One, the Roadster, has an electric folding fabric roof which drops into a storage area behind the front seats. The other will be a targa-top coupé with a compartment to stow the roof panels, more luggage space and a glass rear end.

As with the City Coupé, the Roadster will have removable body panels so you can change the car's colour as often as you like. Of the two, it's the targa which promises to be the most practical, although the standard version will be cheaper, with an estimated price of slightly less than ΂£11,000.

However, the lasting impression of driving this Smart is one of enthusiasm - here is a car that successfully combines value for money with an ear-to-ear grin factor. We can't wait to get our hands on a UK version...