By comparison with, say, St Tropez, Britain would not seem to recommend itself particularly strongly as a great place in which to have an open-top car. Even under the encouraging changes set in motion by global warming, inconsistency continues to dog the weather and, certainly in Manchester, the days are rare when a shower isn't, at the very least, imminent.

For most of the autumn, vast swathes of the country are afloat on flood-water, to the extent that people might come to think a twin-stroke motorboat was a better investment than a leaky cabriolet. And, at this time of the year, when winter's bitter chill grips the nation's steering wheels and daylight occurs after 2pm and only for 10 minutes, a car with a roof tends to seem appealingly practical, and the thicker the better.

Yet convertible cars are vibrantly popular here. Despite having, perhaps, the fourth worst climate in Europe, Britain is the second largest market for cars that make your hair flap. British people bought 70,000 new ones last year. The biggest buyers were Germans, who tend to be the biggest buyers of everything anyway. The relative indifference of the Danes and the Norwegians you can understand. But where were the Spanish, the Portuguese, the Italians, the French of the south? Where were the sun-kissed Greeks? Don't these people realise what they have?

One of the reasons that convertible car sales are growing everywhere is the arrival and broad dissemination of the electronically opening roof, which would have to be right up there with laser surgery and the Sky+ box among the great technological developments of our time.

Being able to open and close a car's roof at the push of a button has removed from convertible motoring the physical burden that may well have been disheartening the broader market. It has eliminated the need to fasten a sheet of canvas over a metal frame apparently three-quarters of an inch too big for that canvas in every direction. It has also enhanced the appeal of open-top driving in unpredictable climates, such as Britain's. These days, you can be out in a downpour and have the roof back on before the rainwater has pooled in the interior and is lapping at your cassette deck.

The evolution of the electronic roof has been gratifyingly swift. Originally only available on vehicles belonging to Gerry Anderson characters, the device eventually found a general, commercial release on the furiously pricey Mercedes SLK. But, as with DVD players and PlayStations, if you wait long enough the price eventually plummets, and soon electronic roofs were being fitted to relatively cheap Peugeots.

The crowning moment came quite recently with the installation of a push-button roof on a budget Japanese fun-buggy, the Daihatsu Copen, the on-the-road price of which is only marginally greater than the cost of getting an ordinary car's windscreen fixed.

It was only a matter of time, then, before Vauxhall wired up the roof of their Tigra, a low-cost two-seater which saw some handy sales action when it was first produced in 1994 and which has been spruced-up and wheeled out again. The Tigra's mechanism works in the now accepted style. You release a couple of internal catches, taking care not to remove the tips of your fingers at the same time. Then you hit a button modestly located with the controls for the windows and wait while the boot and roof perform a little 20-second cabaret number, at the end of which the latter has tucked itself inside the former.

Fun for you, fun for passers-by, fun for all the family, in fact. Not that all the family can fit in your Tigra, of course. But they can stand around on the pavement and watch you enjoying yourself.

The smart thing about the Tigra's roof is the way that it drops almost vertically into the boot, rather than flat-packing itself horizontally. The result is that, even with the roof down, you are still left with something quite strongly resembling boot space - 250 litres of it, Vauxhall claim, which is more than enough to hold an overnight bag, some shopping and a standard-sized midlife crisis.

I grabbed a window of sunshine last week to test the Tigra in all its glorious toplessness. I turned the heater up to guard against frostbite and iceburn. Turning up the hi-fi helped, too. I had to be melted out of the cockpit with naked flames afterwards, but it was worth it. And if it was that much fun in December, there would be anything up to a fortnight in August when it was really worth having.

That said, despite that pointy chassis and the exposure to the elements, you wouldn't turn to the Tigra to have your hair blown out in other ways. It handles like a hatchback and sounds like a saloon - no throaty roar when you stamp on the pedal, just a dull purr and an unstartling pull-away. The suspension is cushiony and the seating position almost upright. Purists won't believe you drive a sports car at all. They'll accuse you of driving a high-grade hairdryer. Still, at least you won't be getting wet.