Iran's President, Mahmoud Ahmadinejad, has the answer to the world's financial turbulence: blame the Jews. Speaking at the United Nations last month, Iran's elected leader accused Jews of "dominating an important portion of the financial and monetary centres as well as the political decision-making centres of some European countries and the US in a deceitful, complex and furtive manner".
He is not alone. "It's difficult, if not impossible, for one honest investor to neutralise the efforts of thousands of Jewish swindlers," was a post on a Yahoo Finance group site. YouTube hosted a video called The Court Jewsters and shows a shot of a dollar-bill emblazoned with: "In Zionist bankers we trusted".
The myth of the conspiratorial influence of the Jews remains as potent and seductive as ever. Our own homegrown Jew-hater, the BNP leader, Nick Griffin, has only one major publication to his name. Called Who Are the Mind-Benders?, it seeks to depict Britain's newspapers and TV under the secret control of a Jewish lobby whose members have cunningly changed their names to avoid being detected.
The rise of a fanatical Islamist antisemitism has been well-documented. From Bin Laden to the Muslim Brotherhood's chief theologue, Sheikh Qaradawi, the constant attacks on Jews and Judaism - and the support for murdering Jewish children and women in Israel or Jewish establishments elsewhere - is central to contemporary Islamist fundamentalist ideology.
For many of my fellow MPs, it is fashionable to think that antisemitism died with the Holocaust. Surely no one in their right mind can believe that Jews are behind the world's major problems or that their religion, beliefs and affinities should again suffer assaults which remind us of the past?
Yet two of Britain's major professional unions, representing university teachers and journalists, adopted resolutions calling for boycotts of Jewish academics and journalists in Israel. The Nazi slogan "Kauft nicht bei Juden" - don't do business with Jews - has been seized on by the extreme left across Europe as its members seek to organise boycotts and censorship of Jews who work in Israel.
Neither union would contemplate for a nanosecond supporting boycotts against Israel's neighbours, where the rights of journalists, independent academics, women and gays are subject to brutal repressions far, far worse than anything that could be laid at Israel's door. But, as with media coverage which seizes on any fault by Israel but glides over what happens in Saudi Arabia, Syria or Iran, there is a double-standard at play, which does no service to truth and still less to the causes that secular, democratic Palestinians uphold.
If the left is guilty of one-sided dislike of Israel and turning a blind eye to Islamist antisemitism, the right is guilty of creating the culture of intolerance in which antisemitism, along with other hates against non-majority races, nations and religions, pullulates.
In 1938, the British population stood at 30 million but the Daily Mail told its readers: "The way stateless Jews from Germany are pouring into every port of this country is becoming an outrage." In 2008, Britain's population stands at 60 million, though still only 10 per cent of UK land surface has dwellings on it. Yet to read today's tabloids is to be told that Poles, Pakistanis and almost anyone without a British passport is unwanted.
So, confronting antisemitism also means confronting racism and xenophobia. I tell Muslim constituents in my South Yorkshire constituency that they have every right to respect for their faith but no right to promote an ideology - fundamentalist Islamism - which denies Jews their right to live free of fear.
A fashionable trope has it that ideological hate against Jews is simply a matter of criminality. To be sure, Jew-hating terrorists are criminals. But what drives them on is ideology - a value system which treats Jews as enemies. The same ideology lay at the heart of the late Austrian far-right leader Jorg Haider's thinking. The antisemitism of the far-right parties in Europe is essential to their core beliefs. Although anti-Muslim, anti-immigrant and anti-European language currently predominates, the dislike and contempt for Jews is central to Europe's growing extreme right.
Today, it is doubtful if one voter in 10,000 who puts a cross against a BNP candidate's name is aware that Nick Griffin believes that "the very idea of Zyklon-B extermination has been exposed as unscientific nonsense" as well as other antisemitic nostrums that would make Griffin a perfect envoy for the current president of Iran.But, by this time next year, the BNP could have its MEPs in the European Parliament and win its first directly elected Mayor in Stoke.
As Britain heads for economic slowdown and rising unemployment - two handmaidens of extremist politics - the time has come not just to confront contemporary antisemitism, in its open and unwitting forms, but also other forms of hate journalism against Europeans, asylum seekers and those who are not white English Christians.
Antisemitism is the canary in the coal-mine. Listen and the song of tolerance grows weaker and weaker as hate against Jews and others once again begins to fuse into with mainstream political activity.
Denis MacShane is Labour MP for Rotherham and a former Minister for Europe. His book, Globalising Hatred: The New Antisemitism, is published by Weidenfeld and Nicolson (£12.99). He chaired the All-Party Committee of Inquiry into Antisemitism and is a UK delegate to the Council of Europe