The Welsh 20mph limit is a terrible idea | Thank Frankel it's Friday

Usually it happened at traditional motor shows (remember them?) when I’d be asked to go and interview various grandes fromages of the industry, all highly trained and therefore rather adept at not answering your questions. I’d then get annoyed.

I can remember a PR man offering me the rare and special opportunity of talking to one of its senior engineers who’d clearly been programmed to say nothing at all. So after ten minutes of stonewalling I asked him why he’d put himself forward to talk to journalists if he had no intention of doing anything of the kind. And that was the end of the interview.

But today I bring you a report, from the very front line, on the most important matter facing motorists today, at least if you live where I do: the 20mph speed limit recently imposed in Wales.

Essentially every journey I do involves encountering one of these limits, imposed without consulting the population it affects because the Welsh government knew exactly what the answer would be. It has also turned a load of former 40mph limits to 30mph and decided to reduce a ten-mile stretch of local dual carriageway in the middle of nowhere to 50mph presumably because it can. No roadworks are planned and while the new limit is described as ‘temporary’ no reason for its imposition is given nor the slightest suggestion as to when it might be lifted. My guess is ‘never’. But it will provide the happiest of hunting grounds for the local constabulary to nab drivers furious at this completely pointless imposition.

The theory behind these changes goes something like this: at the price of each journey taking slightly longer, everyone is safer, emissions are lower and fuel is saved.

The reality goes something like this: even if everyone stuck to a saintly 20mph, I’d be amazed if emissions were lower and fuel saved because, in reality, that means cars are stuck in lower, less efficient gears. It’s the same reason ICE cars use less fuel and produce less CO2 on the motorway than in town. But actually, it’s worse than that because what tends to happen is people jam their cars in an even lower gear so as to be able to accelerate back up to speed the moment the opportunity presents itself, which means more fuel burned. Even more under the full-throttle acceleration people tend to deploy when they reach the end of the zone.

Another phenomenon I’ve encountered, and which I don’t imagine troubled the minds of those responsible too much, is that cyclists you’ve overtaken safely in the countryside catch you up in the villages and those who believe the speed limits don’t apply to them, come gleefully pedalling past, adding yet more tension to the at-times already-fraught relationship between cyclists and drivers.

But actually, I don’t have any problem with a 20mph limit where it is necessary. Like in narrow urban side streets, outside schools and near pedestrianised areas. Force drivers to do 20mph here and lives will be saved. But for it to be applied as it has, across the board, both where it is needed and where it just looks lazy and spiteful; a lowest common denominator, catch-all solution to a complex, nuanced issue that is expensive to impose, will harm local economies and is unlikely even to realise the benefits it was designed to achieve.