Britain is manifestly worse off, manifestly damaged, by the act of leaving the European Union. As Brexit begins, the opinion is circulating in the capitals of continental Europe that when Britain leaves it must be left palpably worse off than if it had stayed. That would deter any movements elsewhere in the same direction. But there is no need to make Britain suffer, pour encourager les autres, as Voltaire said. Britain is punishing, demeaning and shrinking itself, psychologically, morally and spiritually, by turning its back on its neighbours’ most precious project. They boldly reached for the dream of a great European civilisation united and at peace for the first time in how many years – 2,000? And after how many deaths sacrificed on the altar of aggressive nationalism – one hundred million?

Participation in that project by Britain was noble, honourable and uplifting – as well as self-interested – considering how many of those deaths were British. By leaving, Britain has diminished its own moral stature, in others’ eyes and, in all truth, in its own. That is surely punishment enough. It seems to have decided on this foolish course for the tawdriest of reasons: that it did not much like the modest cultural adjustment and occasional inconvenience that arose from the presence in its midst of three million EU citizens.