What has changed? In two words, Islam and Israel. The rise of Islam in Western Europe has made anti-Semitism a useful recruiting sergeant for unscrupulous preachers and politicians. And the existence of Israel has given them a cloak of respectability, by enabling them to disguise anti-Semitism as criticism of the Jewish state. When George Galloway, for example, declared Bradford an “Israeli-free city”, the meaning and effect of the then MP’s action well understood by British Jews. But Galloway was not prosecuted because his threats were ostensibly only directed at Israelis, who are not a race but a nation. A politician who declared a British city “Pakistani-free” would, though, have been unlikely to get away with it.

Yet the truth is that anti-Semitism is not just a sub-species of racism, but something unique and different. It is a hatred — and ultimately always a lethal hatred — directed simultaneously against a people, a race and a religion. It is thus universal and ubiquitous, not particular or localised; it does not even require actual Jews.

Because the attempt to exterminate the whole Jewish people took place in Europe, the post-war nations of our continent made a collective vow never to allow such a thing to happen again. Yet today, 70 years later, anti-Semitism has redoubled its strength and has returned to Europe with a vengeance. Jews are leaving in record numbers. Governments are tacitly acquiescing in this silent exodus by making life more difficult for Jews — restricting kosher slaughter or circumcision, for example — and by failing to take adequate steps to ensure their security. Jewish Europe is vanishing before our eyes, as the Dia-spora goes into reverse.

Does all this matter? As a Catholic, as an Englishman, as a civilised human being, I feel a profound sense of responsibility towards the Jewish people as a whole, but towards my Jewish compatriots in particular. Preserving the Jewish presence in our midst is as much a solemn duty for our generation as it was for our parents and grandparents, who fought to defeat the Nazis. As the last survivors of the Holocaust and the last exiles and émigrés pass away, we must take over their role as witnesses to the truth and guardians of that moral obligation. Never again should Jews have to live in fear among us. Never again should Jews feel that their loyalty is distrusted. Never again should they lack a state that is theirs, living in peace and security within recognised borders. Britain’s commitment to defend Israel’s right, not merely to exist, but to flourish, should be especially strong: it was, after all, the Balfour Declaration that brought the Jewish homeland back to life. Britain did not cover itself with glory during the Mandate period, but we do have a chance to redeem ourselves today by standing up for Israel at the UN and other international bodies, as our Anglophone cousins in Canada, Australia and the United States generally do. When Israel responded to attacks from Gaza last year by destroying the ability of Hamas to launch missiles and use tunnels to infiltrate Israel, the Prime Minister refused to join in the chorus of condemnation. Like Margaret Thatcher and Tony Blair, David Cameron has proved himself a friend of Israel. If only the rest of Europe could say the same.

“Never again” must be our watchword. Never again shall we betray the people whom St John Paul — the Polish Pope and righteous gentile who himself saved Edith Zierer, a Jewish concentration camp survivor — called our “elder brothers”.