To many, Kristin Scott Thomas is that quintessentially English actress from Four Weddings and a Funeral and The English Patient. But to fans of Top Gear she is far more important than that: she is the arbiter of good taste when it comes to cars.

Jeremy Clarkson uses the Scott Thomas factor to settle arguments about a car’s status on the programme’s cool wall, whereby cars are given a coolness rating ranging from sub-zero to seriously uncool.

If the car is likely to appeal to the ice-cool actress, so Clarkson’s theory goes, then it must be heading towards the sub-zero end of the scale.

Scott Thomas is clearly bemused by this. “I find it very amusing that they set me up as a judge of style,” she says. “I don’t really see myself in that kind of role. In reality I can be totally scruffy and uninterested in style.”

Scott Thomas was recently to be found driving around London in a Reva G-Wiz, a car Clarkson has described as “a wart”. During her three-month stint playing in The Seagull at the Royal Court theatre earlier this year, she was often spotted in the tiny electric car (actually it’s officially a quadricycle), decorated with tiger stripes.

“I really liked that electric car,” she says. “The G-Wiz is like a toy. It’s tiny, fantastic and practical. They are ever so light and incredibly easy to park, the only problem is that you can’t go too far in them.

“And on a rainy night you feel you should preserve electricity to get home, so you tend to choose between using windscreen wipers or your lights.”

More serious safety concerns recently came to light when it was discovered that the G-Wiz disintegrated during a crash test carried out by Top Gear, in the process inflicting potentially fatal injuries on the test dummies.

Despite her cut-glass English accent and frosty, aristocratic demeanour, Scott Thomas has spent much of her life in Paris, where she moved aged 19, leaving behind a difficult childhood.

Her father, a pilot in the Fleet Air Arm, was killed in a flying accident when she was five, and then six years later she lost her stepfather, also a pilot, in a similar accident.

She worked as an au pair after being told at drama school in London that she would never make it as an actress. She then enrolled in a French drama college, met her future husband François Olivennes, an obstetrician, and was soon cast opposite the pop star Prince in the film Under the Cherry Moon.

At around this time she bought her first car, a Citroën Ami 8, which was so beaten up that the engine was held together with electrical tape. But in Paris, she says, that can be an advantage. “Driving around the Arc de Triomphe is one of life’s great adventures,” she laughs.

“It can certainly be scary. The trick is not to look at who’s coming at you and just keep on going. And if you drive a beaten-up car, everyone thinks you’re the veteran of many crashes, and they all keep a wide berth.” Scott Thomas, now 47, recently separated from Olivennes, who she married when she was in her twenties, but remains in Paris with their three children, Hannah, 19, Joseph, 16, and George, 7. She counts the likes of Charlotte Rampling, Gérard Depardieu, Jane Birkin and Juliette Binoche among her social circle.

Her latest film, Tell No One, is a French thriller based on a novel by Harlen Coben, an American mystery writer, with the action relocated from the United States to France.

It tells the story of a doctor who, seven years after the murder of his wife, receives an e-mail that can only have come from her. When, at the instructed time, he logs on to the web link given in the e-mail, he sees pictures from a webcam on a public street and watches, dumbfounded, as his wife walks into view.

Cue some excellent Paris chase scenes rivalling those in The French Connection as the doctor desperately tries to work out what’s going on.

Scott Thomas plays his best friend and the lesbian lover of his younger sister. “It’s going to surprise people in England to see me play a homosexual,” she admits. “But what’s great is that her sexuality is incidental to the film, it’s no big deal.”

One might conclude that the French are simply more open and relaxed about life, had not Bertrand Delanoë, the Socialist mayor of Paris, introduced draconian traffic-curbing measures to rival even Ken Livingstone’s London congestion charge. By multiplying bus lanes, cutting parking space and widening pavements, Delanoë has created huge traffic jams in the city, and is now aiming at a total car exclusion zone.

“He’s been trying to kill off all cars,” says Scott Thomas, “and he’s made these massive pavements so all the cars can only use one lane; it means the traffic is crawling. I don’t use the car in Paris any more because it’s a nightmare. I just use it to get out of the city.”

She sheepishly admits that she is like an old woman in a car, frequently catching herself driving nose to windscreen. But there is one misapprehension about her driving she would like to have corrected: earlier this year, when she was living in London, it was reported that she was caught for six motoring offences.

“It’s so unfair because it was nowhere near that many,” she says. Actually it was a mere four – not bad going for such a short stay.

“I admit I got two tickets for bad driving,” she concedes. “One when it was dark and I went past a ‘No right turn’ sign, but didn’t see it, and the other was when I cut into a bus lane like everybody else was doing, but I was the one who got caught.

“I also got two parking tickets for parking in the wrong bay with a visitor’s resident parking permit, but I know I was in the right bay – it’s just that I can’t prove it. In the end it’s easier sometimes to pay the fine, which is just awful – traffic wardens are another form of tax sometimes.”

Pure Clarkson. If Jeremy can overlook that G-Wiz moment, Scott Thomas may have regained her cool.

On her CD changer

I listen to playlists that I make on my iPod and plug that into the car stereo. I have eclectic tastes. Top of the playlists at the moment are songs by Thom Yorke, Lynyrd Skynyrd and the Clash

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