Now this is a neat trick. Take an old car that’s nearing the end of its natural life and, for a tiny price compared with developing an all-new model, produce a glamorised version and charge accordingly.

It will make you money all by itself but that’s not its raison d’être: its true purpose is to allow its more humdrum sisters to bathe in reflected glory, rekindle interest in the whole range and delay its death long past its sell-by date. Audi is the master of this game, its RS2, RS4 and RS6 supercars all arriving just as the models on which they are based appeared to be due for the chop.

For Ford, though, the strategy has gone wonderfully wrong. The Ka hatchback, launched in 1996, might have been expected to be ripe for a shot in the arm. In fact it’s more popular than ever. But even if Ford does not actually need its Streetka and Sportka, I for one am glad they exist.

Both cars use the same new 94bhp 1.6 litre engine but all the extra bracing required to maintain acceptable rigidity means the chopped Streetka weighs nearly 287lb more than its tin-top sister. Which is why the soft-top needs 12.1sec to reach 62mph and the Sportka just 9.7sec. And Ford makes you pay for the Streetka’s neatly packaged roof: it costs £12,495 compared with the Sportka’s super-competitive £9,995, a price that includes air-conditioning which for now is only available in the Streetka with the £1,250 luxury pack that includes heated leather seats and a six-CD stereo.

Both cars enhance the still-modern shape of the original Ka with new bumpers, headlights and flared wheelarches, but it is the Streetka that’s the real glamour puss. As I drove through Cannes I wondered what was the last car costing less than £13,000 to have brought the fabulously indifferent Riviera set to a gawping standstill.

The Streetka’s soft top is well engineered and folds easily into the space where the rear seats would be, which means the boot will take enough luggage for serious driving holidays.

It’s fun, too. The coarse and buzzy engine is nothing like as noticeable as it is in the Sportka (unless the roof is up), while its handling puts it clearly ahead of the Peugeot 206CC, its most deadly rival, if not quite in the Mazda MX-5 roadster’s league.

But the Ford isn’t a proper sports car. Unlike the purpose-built Mazda, the Streetka feels what it is: a decapitated hatchback. You sit on rather than in it, while tall drivers may well find the driving position intolerably cramped and the wind buffeting at speed pretty tiresome.

The Sportka has the better driving position and, while it’s still far from perfect, you probably won’t notice because you’ll be enjoying yourself so much. Other cars such as the identically priced Citroën Saxo VTR offer more power, but get the Sportka on the right road (tight, twisting and empty) and you’ll be amazed at how much fun can still be had for a four-figure sum. It’s a shame then that on the wrong road (straight, fast and boring) the Sportka’s harsh and noisy engine starts to fry your brain.

It is quite possible that the twentysomethings expected to buy 3,000 Sportkas every year in the UK won’t care about such middle-aged concerns, and with its great looks, keen pricing, cheap insurance and rousing handling this lively hatchback makes a compelling case for itself.

I’m not so sure about the less capable, considerably more expensive Streetka that Ford hopes will achieve double the Sportka’s UK sales. The Streetka has the new Smart roadster, the evergreen MX-5 and the staggeringly popular 206CC with which to contend and I wonder if the Ford’s price advantage is enough.

VITAL STATISTICS
Model Ford Streetka, Sportka
Engine type Four cylinders, 1597cc
Power 94bhp at 5500rpm
Torque 99lb ft at 4250rpm
Transmission Five-speed manual
Tyres 195/45 R16
Fuel Streetka - 35.8mpg , Sportka - 37.2mpg (combined)
Top speed 108mph
Acceleration 0 to 62mph: Streetka - 12.2sec, Sportka - 9.7sec
Price Streetka - £12,495, Sportka - £9,995
Verdict Streetka's good, Sportka's great