Sorry to go back over old ground, but this 50mph speed limit malarkey just won’t leave me alone, so here’s a hypothetical to consider.

If you drive a Smart car into a brick wall at 49.9mph on a deserted rural road, the chances are you will not get to watch Eastenders that night. Yet you will not have broken the government’s proposed new 50mph limit.

Drive a Caterham with skill and decent observational awareness along the same road, with the same brick wall at the side of it, but at 85mph, and you won’t be putting anyone in any great danger.

Yet if you get caught you may well get to watch Eastenders that night, but you’ll do so through a collection of iron bars. And have the prospect of a rather worrying shower to look forward to the following morning.

One question: when did common sense march off so suddenly in the wrong direction on this issue?