The postman at the door is stooped by his burden like an allegorical statue of Labour Oppressed by Capital. His wearisome, low-waged task is to deliver a copy of Thomas Piketty’s Capital in the Twenty-First Century — or perhaps multiple copies all round the town, since this breezeblock of a thesis on the iniquities of accumulated wealth stands second in this week’s bestseller lists, pipped only by the life story of someone called Guy Martin.