What does it mean for a nation to exert “influence”? Partly it’s about attitude: the confidence and determination to push hard and long for national objectives. But it’s also about organisation: having the institutions, skills and discipline to turn foreign policy goals into real changes. Taxpayers might think the UK has that in hand, in the form of the Foreign and Commonwealth Office (FCO) which commands the space between Downing Street and the Treasury. But those grand offices hide a momentous decline over the past four decades.

When I joined the FCO in 1979, the European Economic Community was an odd, distant formation where you dusted off A-level French for inconsequential meetings with bemused French and German embassy colleagues and disconcertingly confident European Commission zealots. Things changed. The legal power exerted by Brussels grew and grew. The EEC transformed into a European Community, then a European Union.