People will look for a scapegoat

The first was the argument that formed the emotional core of the Remain case, though it was put all too rarely: Europe is a continent blooded by war, especially in the 20th century but for a thousand years before that.

Jews have a particular knowledge of what conflict in Europe

The European project was consciously born of the desire to end that millennium of bloodshed and sorrow. Rather than fighting each other, the peoples of Europe would settle their differences around a negotiating table.

For Britain to leave would be to pull out one of the three guy ropes - the other two being Germany and France - that had kept the European tent upright. And if the EU were to unravel, the risk was real that Europe could revert to type, and return to war once more. That would be a calamity for all Europe's peoples. But Jews have a particular and intimate knowledge of what conflict in Europe can bring.

Second, Jews took a good look at who stood ready to welcome a Brexit. Outside the UK, the list was not encouraging: Vladimir Putin, Marine Le Pen, Donald Trump and every far right racist and populist in continental Europe. In the UK, the advocates were, admittedly, less disturbing. Boris Johnson and Michael Gove have many Jewish admirers - and I heard the smoked salmon entrepreneur Lance Forman make a spirited case for Brexit, recalling the fact that he was the child of Holocaust survivors, at a Vote Leave rally in Billingsgate four days before referendum day. Even so, I suspect many Jews struggled to be reassured by the presence of Nigel Farage and George Galloway in the Leave camp.

More substantively, Jews could not help but notice the centrality of immigration to the Leavers' case. Of course, Jews are not immune to misgivings about migration. But I suspect that those with long memories shudder when they see a poster like the notorious one unveiled by Farage during the campaign: a snaking queue of dark-skinned refugees under the slogan, "Breaking Point." We didn't need it pointed out to us that just such an image had been a staple of Nazi propaganda.

Now that the verdict is in, it seems that Jewish angst about Brexit is deepening: the JC poll found that 37 per cent of us feel less safe. No wonder. First, Jews have seen the upsurge in racist attacks - hate crimes up by 57 per cent in the immediate aftermath of Brexit – and will have felt that old certainty that people who hate the dark or the different rarely make an exception for Jews.

Second, they will have seen the likelihood that the Brexit vote will lead the Scots to seize the independence they spurned in 2014, and will perhaps prompt Northern Ireland's exit from the UK too. That will leave a shrunken United Kingdom, which should be a source of regret for Jews.

The union of four different nations has been a comfortable home for us, a place hospitable to hyphenated identities. Because you could be Scottish and British or Welsh and British, it has long felt very easy to be Jewish and British. In a little England and Wales? We'll see.

But it's the economic instability that will have plenty of Jews worried. Not chiefly because of their own, narrow interests, but because of the nagging memory of what happens when factories close, jobs are cut and currencies plunge: people look for a scapegoat.

For years, Britons have had the EU and those meddling Brussels bureaucrats to blame. Once we're out, there'll need to be someone else, some other sinister force, some other conspiracy, that can be held responsible. We Jews have seen that movie before: we know how it ends.

Jonathan Freedland is a columnist for the Guardian