For decades, Britain has had campaigners against metric (or the “Napoleonic system” as some of them call it), who were generally on the populist right. There was a grocer who refused to display prices in metric measurements and, when he was fined, refused to pay and was sent to gaol; the tabloids called him the “Metric Martyr”, and lionised him as a hero alongside those who vandalise speed cameras. One of the promises of the Brexit campaign was to abolish the metric system and go back to imperial measures, though after they won, they realised that the imperial measurements have been legally defined in reference to SI units for decades, and establishing a new basis for measurement would be far too expensive and disruptive to do just to placate a bunch of pub bores and opinionated van drivers, so they dropped it.

So Britain has a mixed system (beer and milk are measured in pints, and road distances/speeds in miles, but most other things are metric), only the fluid ounce, which is 1/20 of a pint, is legally defined as 28.4ml or so. Even worse, road distances given in yards (each being around 0.9 of a metre) are actually in metres, going on the assumption that the average person can’t tell the difference. Of course, they can’t call them metres, as there’d be irate letters to The Times and questions in Parliament.