In France the natives have a habit of testing their cars’ headlamps with a couple of hearty flashes – just after passing a radar trap that’s been positioned to capture motorists heading in the other direction. It’s a quaint, charming custom. And one that used to be quite common in Britain, too.

Supercars_157 Not any more. The other day I was cruising down the A31 on my way to Southampton. Just after a village called Ropley there’s a steep hill with a blind crest at the top. And, on the verge after the crest, stood one of the familiar white camera vans with its rear door open: and I hadn’t seen a single headlamp flash from anybody coming in the other direction.

So what did I do? Well, according to some Byzantine piece of road traffic legislation it’s illegal to warn other road-users of the presence of a speed trap – you can even get points put on your licence for attempting such a heinous act. So, of course, I did no such thing. I can confirm that my headlamps are still working fine though.