My father, born in Belfast in 1919, was a racist all his life. He didn’t like Germans much, having spent most of the second world war working in a prisoner-of-war coal mine in Silesia, but he worked hard as a diplomat on British accession to the EU, and he acquiesced to being scolded by his children for his horrible racist views. He might not really believe in the equality of all races, but he knew better than to say it out loud. Progress does happen, slowly – and then, quite fast, it goes into reverse.

Last week Arron Banks’s Leave.eu campaign tweeted out a cartoon so disgusting that it would have reminded my father of the newspapers he was given to read as a prisoner of war. The cartoon shows a sailing ship, representing the EU, heading over a waterfall, while behind it a lifeboat labelled Brexit escapes into the sunrise, a Union Jack for its sail. So far, so unimaginative. But in the central section of the EU boat things get vivid.

Two swarthy, bearded figures, one carrying a scimitar and one a bag of money, would have been immediately familiar to my father, except that in the cartoons of his captivity they would have been Jews. Here they appear to represent Muslims. The one with the scimitar is forcing a blond Aryan young man carrying a Swedish flag to walk the plank while the one with the money bag holds it excitedly. At the front of the boat another of these figures attempts to grope the figurehead.

The figures in those cartoons are drawn from the same stock as those that populated Nazi papers

A cannon on the afterdeck labelled “Diversity” is firing a hole in the bottom of its own ship. Oh, and a shark labelled “political correctness” is waiting to devour the figure representing Sweden when he is forced off the end of the plank. The cartoonist really does not believe in subtlety.

These tropes are not just racist. They are callbacks to the particular style of nationalist antisemitism that we thought had been purged from Europe for ever in 1945. The figures in those cartoons are drawn from the same stock as those that populated Nazi papers.

It may seem absurd to conflate the fear and hatred of Muslims with the fear and hatred of Jews when the two groups are united in the popular imagination only by their fear and hatred of each other. But they both appeal to the same dark archetype in the European imagination: swarming, sinister, lecherous, and dirty. Both are supposed to have subverted the elites to strike at the common people. Both are supposed to constitute an existential threat to civilisation.

And anyone who appeals to either of these terrible archetypes is an enemy of this country, and of all the values and the decencies my father fought for and suffered to preserve. Remember, if you vote leave, you get the vote leavers.