I’ve just finished reading Crooked Cross, a 1934 novel by English writer Sally Carson that’s suddenly found a new audience. Inspired by visits to friends in Germany, Carson showed how Nazi rhetoric against the Jews intensified until millions of ordinary people were swept up in it. I’ve been thinking a lot about that book this morning. The reason? The latest intervention by Green Party leader Zack Polanski.

The left is very excited about Polanski. He’s transformed the Greens from a fringe eco group into something far more sinister. Under his leadership, it’s become angrier, more ideological and obsessed with identity politics and the Middle East. Now he’s just gone a step further, by backing a campaign demanding a register of British citizens who have served in the Israel Defence Forces (IDF) since the Hamas atrocities of October 7.

The petition calls for British citizens who have served in to the IDF to declare themselves to the British authorities. Basically, he thinks it’s a good idea to draw up a database of British Jews with dual-Israeli citizenship. Then track their moments, and potentially investigate and prosecute them. Its supporters cite concerns “public safety”. But many British Jews will hear something very different. They will hear politicians demanding lists, monitoring movement and singling them out for scrutiny.

Israel has compulsory national service, with the exception of some religious groups. That means huge numbers have served in the military. Many British Jews have family links to Israel. At a time when antisemitism is already surging, this will make an already frightened community feel even more isolated. They’re already wondering whether the country is safe for them.

Antisemitism was rife in Labour under Jeremy Corbyn, who infamously called Hamas and Hezbollah his friends. Corbyn has signed the new petition, of course, along with the usual leftie suspects like Dianne Abbott, Zarah Sultana and John McDonnell. Polanski couldn’t resist either.

One line from Crooked Cross shook with me. A young German woman with a Jewish boyfriend dreams of England. She called it a place “where people were quiet and casual, and no one minded about Jews, where you could say what you liked”.

Heartbreakingly, that country no longer exists. Many on the left mind very much about the Jews, and they aren’t quiet or casual about it. In fact they can be found chanting in our cities most weekends. And the Britain where people could say what they liked is long gone.

It’s legitimate to question Benjamin Netanyahu’s Gaza and Lebanon policy, or settler aggression on the West Bank. But Britain must resist importing Middle East hatreds to these shores. Drawing up lists of Jews is crossing a terrifying line. If this petition was ever acted upon, worse would follow.

Yet Polanski has dived in with both feet. Just as he did with his vile criticism of heroic police officers who risked their lives to arrest a knife-wielding Islamist bent on killing random Jews. We already knew Polanski was a total political chancer. Now we know he has no limits.

Weirdly, Polanski is Jewish himself. Perhaps he feels this allows him to get away with it. Or perhaps he feels the need to confirm his political purity. Incredibly, his own family fear they’d be forced to flee Britain if he ever made it to Number 10.

It’s no coincidence that this is happening at the same time as Winston Churchill has been erased from our nation’s currency for being “divisive”. We all know where the division is coming from.

Carson’s novel was a warning that civilised societies can drift somewhere dark without noticing until it’s too late. She named the book Crooked Cross as it’s a direct translation of the German word Hakenkreuz. Today, we use the word swastika. Its shadow is hanging over us today, just as it was in the 1930s.