Twenty years ago I had lunch in London with a senior civil servant. This was at the tail-end of the decadent London lunching era and, after a lot of wine, he asked me what I thought of the minister he worked for. I said I’d interviewed the minister and he seemed a nice bloke. “The man”, said the civil servant, leaning across the table for emphasis, “is an animal!”

Anyone who remembers the 1980s television comedy series Yes Minister and Yes, Prime Minister knows that British civil servants and ministers are forever locked in a silent power struggle. That struggle will shape the form that Brexit ultimately takes. British voters chose Brexit; Theresa May’s new government has promised to implement it. But, in practice, civil servants will mostly sort out how exactly it is done. And these people are good at getting their way.

In the first episode of Yes, Prime Minister, the new prime minister, Jim Hacker, egged on by the government’s chief scientific adviser, concocts a whizzo scheme for a conscription army. Hacker, delighted with himself, exclaims: “Why didn’t I think of this before?” and the chief scientific adviser replies: “Because we only just met.”