In such circumstances, Britain’s rabid tabloids would certainly blame the chaos on the bloody Europeans – especially the French – and demand we immediately stop paying any more money to the EU. The new Brexit secretary, Dominic Raab, has already said London won’t pay its agreed £39bn divorce bill if it doesn’t get a satisfactory deal. Angry Brits will go on to ask: why should our troops be protecting faraway Europeans when the Europeans are screwing us? And then: why not go back to the traditional British policy of trying to divide and rule on the continent?

Such a Britain could also arrive more slowly, if the other 27 member states of the EU impose a humiliating divorce deal – a milder, peacetime, bureaucratic version of the punitive Versailles treaty imposed on Germany after the first world war, which sowed the seeds of German nationalist revisionism. Britain’s Brexiteers are already talking about a Brexit 2.0, to follow and revise any makeshift deal cobbled together so that Britain can formally exit the EU on 29 March 2019.

Am I exaggerating the danger by even hinting at a comparison with Weimar Germany? Indeed I am. I don’t seriously envisage millions of newly unemployed, or a new Hitler coming to power, or a world war started by Boris Johnson. But it’s surely better to overdramatise the risk, to get everyone to wake up to it, rather than do what most of our continental partners have done for the last two years, which is consistently to underestimate the dangers for the whole of Europe that flow from Brexit – especially a mishandled Brexit.