Compared with every other household chore, progress in bum-wiping has been glacially slow. It’s only in living memory that schools and institutions stopped using something called Izal, a box of medicated toilet wipes similar in texture to greaseproof paper, and thus spectacularly ill-suited to its purpose. It was characteristic of the Britain of my childhood, where things were made gratuitously unpleasant on purpose, since to do anything nice was seen as effeminate.