There is a straightforward reason why Britain has tended not to strike financial deals with the Americans: we don’t tend to do terribly well out of them. One could cite the last transatlantic trade pact, the disastrous Anglo-American agreement of 1938. Or maybe the Bretton Woods conference of 1944, when Britain’s plans were largely bulldozed over. But perhaps the best place to start is 1945, when the UK sought a post-war loan from the United States.

Dosed up on heart medicine — which by some terrible coincidence also happened to be a truth serum — John Maynard Keynes bungled his way through the talks, outmanoeuvred and out-negotiated at every turn. “We have done our level best to move the Americans,” Lord Halifax cabled back home.