Last month a 32-year-old IT worker, Michael Booksatz, was beaten up in the streets of north London by two hooded men shouting about Palestinians. Jewish students at the London School of Economics - home to many brilliant Jews who fled Hitler's Germany - are now frightened by anti-Jewish abuse from Islamist students. Graffiti such as "Kill the Jews" or "Jihad 4 Israel" appear close to synagogues in London.
The Metropolitan Police report four times as many anti-Jewish incidents in recent weeks as Islamaphobic events. The respected Community Security Trust, which records anti-Jewish attacks with scrupulous rigour, reports as many attacks on Jews - verbal, vandalism and some violent - in the first weeks of 2009 as in the first six months of last year.
As the world enters a new era of crisis, anti-Semitism is back. History, as ever, begins to repeat itself. The slumps and stock market fever expressed in Zola's novel, L'Argent, or the populist anger against Wall Street at the end of the 19th century gave rise to the virulent anti-Semitic politics witnessed in France in connection with the Dreyfus case or the takeover of Vienna by openly anti-Semitic politicians. The Great Depression gave rise to the worst expressions of anti-Semitism ever seen, namely the politics that led to the Holocaust. But even in Britain the Duke of Wellington of the time was leader of a secret anti-Jewish organisation which had the initials PJ - Perish Judah - on its letterhead.
The economic crises of the 1970s led to a marked increase in the vote for the National Front in Britain and the openly anti-Semitic BNP, its successor extreme party, is doing very well in local elections - below the radar of the national opinion polls.
The distress and upset over the terrible pictures of children killed in Israel's attacks on Hamas in Gaza have allowed anti-Israeli feelings to be more violently and vehemently expressed than ever before. Criticism of Israel is not anti-Semitic. But all anti-Semites hate the existence of a Jewish state and hiding behind code words such as anti-Zionism increases the density and viciousness of their anti-Jewish utterances.
In Italy, the streets of Milan are daubed with slogans urging Italians not to buy goods at Jewish shops - an echo of the Nazi slogan "Kauft Nicht Bei Juden". In Germany, radio phone-ins are full of accusations that the bankers accused of being responsible for the current economic crisis are Jews. In anti-Israel demonstrations in Berlin, placards stating "It was a good idea to use gas" or "I'm anti-Semitic and that's a good thing" were carried. Thus every Jew is made to feel as if they do not fully belong in the countries where they were born or the societies that they participate in.
Terrible massacres of Muslims have taken place in different parts of the world so far this century, from Kashmir to Gujarat. In Iraq and Afghanistan, Nato soldiers are accused of brutality but the men with the most blood on their hands of fellow Muslims have been Islamist ideologues. Yet there is no outrage against the perpetrators of those attacks compared with the onslaught on Israel and on Jews.
Is it unreasonable to argue that the reason that there is worldwide anger against Israel but not against other regimes or religions that carry out massacres of Muslims is because the Israelis are Jews? Has legitimate criticism and anger against Israel allowed Jew hate to become almost acceptable politics again? Add to this a world economic crisis in which it is so easy to point at the names of the swindlers and banksters that happen to be Jewish, and a new perfect storm of anti-Semitism begins to take shape.
Today in London a conference of parliamentarians from different legislatures in Europe and around the world will gather to discuss what can be done. Michael Gove, for the Conservatives, will join Labour Cabinet ministers Hazel Blears and Jim Murphy in saying it is time for the Parliaments of the democractic world to take action against anti-Semitism - especially Islamist attacks against young Jewish students on university campuses.
The Pope embraces a Holocaust-denying Winchester and Cambridge-educated bishop; slogans such as "Hamas, Hamas, Jews to the gas" are chanted in Amsterdam;
Jews are again made to feel they are not full citizens of the countries of their birth because they refuse to support the right of Hamas and Hezbollah to use terror attacks against Israeli civilians. The canary in the coal mine seems in danger of its life once again.
Denis MacShane, MP, is a former Minister for Europe and the author of Globalising Hatred: the New Anti-Semitism (Weidenfeld & Nicolson)