Reading about Cressida Gethin, the latest Just Stop Oil protester to be convicted of causing a nuisance, I found myself thinking of the strange days when British débutantes, young women making their first appearance in upper-class society, used to curtsey to a cake. I also thought of their other odd rituals, such as the parlour game, ‘Are You There, Moriarty?’, as splendidly showcased recently in Netflix’s One Day. Such customs appear perfectly reasonable to the ruling class, while utterly insane to the rest of us.