Hence it should come as no surprise that Peter Mandelson has advised the European Union to treat the Brexit negotiations as an opportunity to punish the British. Last month Lord Mandelson told Die Zeit: “Forget Great Britain, and look after your own interests.” This is the former EU Commissioner who likes to boast: “I was a Remainer, not because of my pension rights but because I am a patriot — a patriot, not a nationalist.” In his eagerness to see his compatriots forced to rue the day they voted to turn their backs on Brussels, he speaks for a minority of unabashed Remainers who are still bitter about last year’s referendum. The vast majority who voted Remain, whether out of conviction or because they were alarmed by “project fear”, have accepted that Britain is leaving the EU. A few — Remain’s Remainder — are working round the clock to reverse the result.

Like the Jacobites of the 18th century, they prefer to give their allegiance, not to the British Crown, but to the king across the water — or rather, to the presidents of the EU (of whom there are too many to list here). Many of these latter-day Jacobites are intellectuals, but they are still in denial about what they claim “the far Right” have done to the UK. They refuse to think Brexit will actually happen, despite all evidence to the contrary, because it is “too difficult”. Not all our European neighbours agree with the ultra-Remainers’ pessimism. Matthias Döpfner, CEO of Axel Springer, thinks Brexit will make the UK “highly attractive” to investors: “In three to five years from now, my bet would be that England will be better-off than continental Europe.”

In 1940 many thought Hitler could never be defeated. Some crossed the line between pessimism and treason: the Duke of Windsor tried to persuade Americans not to enter the war on Britain’s side. Yet such diehards were few. Just as in May 1940 the vast majority of those who had supported appeasement (including Chamberlain himself) and those who had opposed it united behind Churchill in order to win the war, so today Mrs May has an opportunity to unite the nation in order to keep the peace. For all its fiendish complexity and booby traps (Scotland, Northern Ireland and Gibraltar are cases in point), Brexit is not only possible but an urgent necessity. We have only to compare the present task with more daunting challenges in the past, to which the British and their leaders have always risen. However we may have voted last year, however we may vote next month, the outcome cannot now be ducked. After June 8, a reunited nation can move on from Brexit and address the threats with which President Trump is grappling. In Churchill’s words, “The life of the world may move forward into broad, sunlit uplands."