Giddy from having put its collective head above the parapet for the first time ever, Britain’s Jewish community leadership is telling itself that it has managed to change the political weather.Earlier this week, the Board of Deputies and the Jewish Leadership Council published a blistering attack on Labour’s leader Jeremy Corbyn for facilitating antisemitism in his party.A demonstration they called outside Parliament, which brought around 2,000 mainly Jewish people onto the streets, produced the extraordinary sight of dozens of Labour MPs turning up to express solidarity against their own leader, demanding that he purge the party of the antisemitism now rampant within it.In the face of this unprecedented protest, Corbyn kept shifting his ground. He first conceded there were “pockets” of antisemitism in the party, then that it was more than “a few bad apples,” and then that there was antisemitism in parts of anti-Israel discourse.So will the Labour party now be forced to purge this poison with which it’s become rotten? No.The reason this suddenly erupted was that the usual alibi, that “antisemitism” was just criticism of Israel, was blown away.Corbyn was discovered to have subscribed to a number of Facebook groups – five at the last count – which contained wildly antisemitic ravings about the Rothschilds, conspiracy theories linking Israel with ISIS and 9/11 and much more in that deranged vein. Then came the revelation that he had condemned the removal of a rabidly antisemitic wall painting in London’s East End. This depicted hook-nosed Jewish bankers manipulating the world’s finances on a Monopoly board supported on the backs of the poor.Corbyn had championed the artist on the grounds of freedom of speech.His excuses, that he had never noticed the antisemitic nature of the mural or the Facebook posts, have been widely ridiculed. Rather more to the point, in belatedly acknowledging the mural’s “old antisemitic conspiracy theory” of “Jewish bankers and capitalists exploiting the workers of the world,” his attitude was distinctly problematic.For he described this theory as “the socialism of fools.” But the trope of rapacious, cruel and demonic Jews is not foolish. It is vile, vicious and transmits the message that Jews have no place in the human race at all. It is an image straight out of the Nazi playbook.In an interview with the Jewish News on Wednesday, Corbyn described antisemitism as “a poison and evil and wrong that brought about [the] genocide of the Holocaust against the Jewish people.” In almost the next breath, though, he defended the Palestine Solidarity Campaign which he said was “assiduous” in not allowing antisemitic behavior.Yet a report by British blogger David Collier – who detonated the current crisis when he exposed the first antisemitic Facebook page on which Corbyn had posted – has revealed that the Palestinian Solidarity Campaign is riddled with antisemitism.He discovered within it comments such as the Paris Bataclan massacre was a “false flag” operation to increase support for Israel; Kristallnacht was instigated by communist and Freemason Jews to promote war against Germany; Israel harvests organs from the dead and the living. And so on and foully on.Labour MPs and others opposed to Corbyn think he is the cause of the party’s antisemitism. They’re kidding themselves. This kind of filth is endemic in “progressive” British politics.There are complex reasons for this, but one key factor was revealed in Corbyn’s response to the Jewish leadership’s protest.Having delivered various bromides about not demonizing Jews for Israel’s behavior or likening Israel to the Nazis, he went on: “Criticism of Israel, particularly in relation to the continuing dispossession of the Palestinian people, cannot be avoided.”“Dispossession,” eh. This makes meaningless his pieties to the Jewish News about supporting a two-state solution. For if he believes that the Jews “dispossessed” the Palestinians, he believes Israel itself is illegitimate. It means when he talks about “justice for the Palestinians,” he means the end of Israel.THE BELIEF that the Palestinians were the indigenous inhabitants of the land and the Jews dispossessed them lies at the heart of the madness against Israel and the Jewish people. For it is based on the lie that the Jews seized and occupied another people’s land – even though, in history and in law, the Jews are the only people entitled to that land.This lie embodies the deeper calumny that the Jews falsify history to serve their own interests by oppressing and dominating another people. The “dispossession” lie thus leads directly to the deranged and paranoid conspiracy theories about the Jews with which the left is now riddled.For this view of Israel is their default position and championing the Palestinian cause is their signature motif. And that means these British “progressives” all support Palestinians who pump out Nazi-style antisemitism, incite the mass murder of Jews and are led by a Holocaust denier, Mahmoud Abbas, who venerates the Arab Nazi ally Haj Amin al-Husseini.Why then are these Labour “moderates” shocked when Corbyn’s friends spew out identical bigotry against the Jews? The Left thinks it embodies virtue itself and so it is impossible for it to be viciously bigoted toward Jews. But it is.Corbyn may be an extreme ultra-leftist with the most extreme anti-Israel baggage, but he is not the cause of Labour’s antisemitism.He is its product.The Left embraced antisemitism when it embraced Palestinianism. And that’s without factoring in the Muslim voting bloc which is becoming ever more significant for British politics and for the Labour Party in particular, and which is infused with hatred of Israel and the Jewish people.The antisemitism in Labour’s ranks is an existential crisis not just for the party but for the Left as a whole.It is a delusion to imagine that purging the most demented antisemites will make the Labour Party safe again for Britain’s Jewish community. It’s not just Jeremy Corbyn who poses such a threat. It’s the party itself and the left wing culture it embodies.The Conservative Party may be in power in Britain, but the Left controls the universities, the BBC and the artistic and cultural world. It is Britain itself that’s no longer safe for Jews.The author is a columnist for The Times (UK).