Recently I wrote about Britain’s badly signposted towns and I have been inundated with absolutely no correspondence on the matter at all. I can only presume this is because everyone who has an opinion on the matter is busy doing a three-point turn in Stroud railway station car park, unable to find any road that actually leaves the town.

I have some new evidence to back this up. Apparently two-thirds of Britain’s motorists get lost up to 10 times a year, and while trying to find where they are clock up an astonishing 325m wasteful and pointless miles.

Naturally, like everything else these days, including chickens and vacuum bags, this causes unnecessary global warming.

But if we skip over the report’s eco-babble, we find some interesting observations. In London, drivers do 26m miles each year while lost, and that’s the same as driving from New York to Los Angeles 9,200 times. Needlessly.

Even in Scotland, where there are only three roads, motorists can’t get from A to B without ending up in a haggis. Apparently 54% say they get lost the noo up to 20 times a year.

So plainly the problem is even worse than I thought, and there can only be one culprit. Satellite navigation.

Ironically, this is bad news for the people who paid for the survey because they work for a company called Becker, which makes sat navs.

The trouble is that sat navs lull us into a false sense of security by working without fault for a month and then suddenly deciding that the A40 doesn’t exist.

And when you rely on a sat nav, you don’t notice that the sun is in the wrong place in the sky. You stop using your inbuilt compass, your innate sense of which way is up. And don’t argue with any of this. Everyone can navigate by instinct, and if you can’t there’s something wrong with you and you should be in prison.

The only people who can’t navigate instinctively are women and anyone trying to find Malpensa airport in Milan.

I tried to do this last week and it is impossible. The map quite plainly said we would cross a motorway that we needed to ignore. But this motorway does not exist, so when I crossed the motorway I definitely didn’t need to ignore I thought it was the first one. Quickly, because of the position of the sun and my innate sense of distance and time, I realised my mistake and asked Richard Hammond, who was driving, to turn round and go back the other way.

Almost immediately we happened upon a green autostrada sign which pointed us to Venice and Bologna. Both lovely places. But both in the wrong direction. The sign going the other way wasn’t there.

So then we were in a housing estate, with just 90 minutes to go before our plane was due to leave. Both of us were regretting stopping on the shores of Lake Como earlier that afternoon for a beer. I, especially, was regretting the second and third. And fourth, because it made reading the map so very difficult.

James May was especially regretting my extra beers, partly because he can’t read maps and partly because he was due to host a charity day for sick children the next day. So he had to catch that plane.

Soon, however, thanks to my brilliance, we found the autostrada and joined it. Only to find it was the missing autostrada, which had now miraculously reappeared. So we turned off, and in a temper James broke out his hand-held sat nav system.

This took us to the city centre, which even I, in my semi-sozzled state, knew was wrong. I’ve seen many things in the middle of Milan over the years, including lots of pretty women, many pavement cafes, La Scala, the Duomo and the Leonardo da Vinci museum of science and technology. But I have never seen a large international airport.

This is the problem with sat navs. James and Richard are bright blokes – well, James is – but give them an electronic master and they lose all sense of reason. If the sat nav had ushered them into a river, they’d have gone in. And if it had then said, “You have arrived at your destination”, they’d have got out and tried to check in.

We did finally arrive at Malpensa, by following signs to Como, just 17 minutes before our flight was due to leave. And using smiles instead of boarding passes we caught the plane.

None of this has anything to do with the new Aston Martin V8 Vantage convertible.

I’ve been nervous about the arrival of this car because I didn’t think it would be any good. When they removed the roof from the DB9 – a car I love – they ended up with something that didn’t look quite right. And if you take away the looks from an Aston Martin, you take away just about everything.

If the beheading of a V8 caused the styling to go wonky then what would you have? A not very fast two-seater that wouldn’t be quite as reliable as a Porsche 911, or quite as beautiful as the much cheaper Jaguar XKR. The V8 convertible had to look not just good but so bone-quiveringly brilliant that men and women would fall to their knees and whimper whenever they saw even a small part of it.

And I’m delighted to say, it does. Aston sent a green one round, with a matching green roof and a green interior. And even this failed to take away the sheer beauty of the thing. Every time I walked out of my house and saw it, I had to bite the back of my hand to stop crying out.

To drive, things are slightly less rosy. The coupé version, with its dry-sumped and slightly enlarged version of Jag’s Welsh-made V8, is not slow. But it’s not that fast either. Certainly it isn’t as fast as the exhaust bark would have you believe.

In the convertible you can hear that wonderful noise even more clearly. So you expect to be going faster. But the new car is heavier than the coupé so it’s even slower. The gap between aural expectation and reality is therefore even wider, but it doesn’t matter because it’s so pretty.

The reason why it’s heavier is simple. Not only is there the added weight of the roof motor, but they’ve had to strengthen the chassis. They claim, however, that because of the way Astons are made not much beefing up was necessary.

I’m not sure about that. On fairly normal roads, especially when the roof’s down, you can feel the car flexing slightly. Look at the rear-view mirror and you’ll find it moves out of synch with your head. Most convertibles do this, of course, and it’s always annoying. But less so in the V8 because, of course, it’s just so pretty.

Inside, we find the same irritations that blight the hard top, a Volvo sat nav system glued to a flap and buttons that cannot be read when the sun is shining. But none of this really matters because, of course, it is very pretty.

I did enjoy driving the drop head, though. Despite that noise, which is intoxicating, and the man-sized gearchange action, it is a refined and comfortable place to sit. This is a car that glides, rather than scrabbles. I’d even call it relaxing. Reliability? Well, my wife’s V8, which was one of the first ever made, has not been bad at all. The boot filled with water on one trip to London, which was odd since it wasn’t raining, the petrol filler cap fell apart once, the handbrake gets stuck on from time to time and the tyre pressure sensors have a mind of their own.

Tiny things, in other words, and worrying about any of them in a pretty car like the Vantage is like climbing into bed with a supermodel and noticing she has slightly unruly pubes.

Yes, you can buy cars for less. You can buy cars that are faster and nicer to drive and more practical. But the first time you see one of these things, roof down, on a sunny day, you’ll know what I’m on about. This is not a car you need to buy. It is not even a car you want to buy. It’s a car you simply have to buy.

Just so you can look at it.

Vital statistics

Model Aston Martin V8 Vantage Roadster

Engine 4280cc, eight cylinders

Power 380bhp @ 7000rpm

Torque 302 lb ft @ 5000rpm

Transmission Six-speed manual

Fuel 18.8mpg (combined cycle)

CO2 358g/km

Acceleration 0-60mph: 4.9sec

Top speed 175mph Price £91,000

Verdict Bone-tremblingly beautiful

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