Having ranted and raved about cars with flags (who is going to pick up all the grubby frayed ones lying at the roadside?), I feel the time is right to move on to another type of road user: the topless kind.

Not in the St Tropez sense, you understand, but drivers at the wheel of convertibles.

Now I've nothing against convertibles. I used to part-own one myself two decades ago. It was a blue Triumph Vitesse, with rattling doors and dodgy windows.

It's not the cars I have a problem with, but the drivers. Not all of them. I'm sure there are one or two who simply like the feel of the wind in their hair.

But a large cross-section of these vehicles seem to be populated by people who come into three categories: smug and sneery; extremely smug and sneery; and nauseatingly smug and sneery - particularly when you have the misfortune to be waiting alongside them at the lights.

It's the way the drivers glance over, look distastefully at your car, wait until they catch your eye, then look away with a noticeable smirk. Or they look at you full-on, and toss their hair back - and that's both sexes.

If only they knew, we other road users don't envy them. We'd rather sit melting in our tin boxes than cruise around behaving like Canal Road is Hollywood Boulevard.

I have sorted the worst offenders into the following groups:

* Blondes have more fun: At least that is what young women driving around in open-top sports cars want us to believe. Young and almost always blonde, they pretend to be oblivious to all other road users, but in fact they are gleefully basking in the knowledge that they have been spotted. They are commonly seen on the approach road to fitness centres and love being stuck at the lights next to other single women in clapped-out old bangers. Parked alongside them, you feel like you're sitting in a wheelbarrow.

* Last chance saloon: Men aged 50-plus trying to look cool, but not succeeding. Deeply tanned, they are seen wearing sleek but ridiculous-looking shades at the wheel of their even sleeker convertible. Looking every inch a mid-life crisis on wheels, they drive slowly, leaning back in the seat. Often spotted in the vicinity of golf clubs, they notice every lone female driver on the road, and are totally oblivious to men.

* Summer holiday special: A group of young people, laughing and joking, cruising around in their friend's gleaming new 18th birthday present. Generally spotted driving to the Dales, the coast or to country pubs, they usually inhabit convertible minis or VWs. They are so engrossed in themselves they barely notice other road users. Unless, of course, they are all the same sex. All girls, and they think they're Thelma and Louise.