If anybody doubts the depths of anti-Americanism to which those who dominate the public square in Britain have sunk, consider the case of Hugo Chavez. The Venezuelan president came to London this week on a very public “private” visit, ostensibly to talk to oil companies and to offer cheap fuel for the poor, but in reality to pursue his propaganda offensive against the United States. Mr. Chavez is riding the wave of anti-Americanism that still shows no sign of breaking.

Brits flatter themselves that they know more about the world than Americans, but it was a British prime minister (Neville Chamberlain) who notoriously justified his policy of appeasement as the solution to “a quarrel in a far away country between people of whom we know nothing.”

Americans know what to expect from Mr. Chavez. Condoleezza Rice has warned against his “Latin brand of populism that has taken countries down the drain,” but the only thing Britons know about Mr. Chavez – in the unlikely event that they have heard of him at all – is that he hates President Bush.

At a carefully staged “rapturous reception” at City Hall on Monday, the mayor of London, Ken Livingstone, embraced his charismatic guest, basking in reflected notoriety. Mr. Chavez seems unfamiliar with the British habit of understatement. In the course of one rambling speech, he described Mr. Bush as “the biggest perpetrator of genocide the world has known … an assassin … the worst criminal in the human race … an immoral man who should be put in jail by an international court.”

Mr. Chavez reserved his particular venom for American policy in the Middle East, warning of a nuclear war between Iran and Israel. War with Iran would result in an oil price hike to $100 a barrel that would impoverish the West and cause people in London to die in winter, according to the Venezuelan president.

Bashing Bush alone is enough to endear him to the likes of Mr. Livingstone. But there is also a sentimentality where Latin American demagogues are concerned that is bound up with the socialist youth of the Sixties Generation. Once they had Che Guevara posters on their walls, demonstrated about Chile, and sent money to the Sandinistas. Even now, they still read Gabriel Garcia Marquez and Isabel Allende; they still buy fair trade coffee from Nicaragua, and, 10 years ago, they exulted when the aged Augusto Pinochet was arrested in London.

At a rally on Sunday in the Camden district of North London, these aging revolutionaries were out in force, led by B-list celebrities such as Bianca Jagger. Mr. Livingstone praised Mr. Chavez as the only man capable of taking on the “gangster regime” in Washington.

The atmosphere was that of a revivalist meeting of an obscure religious sect. “Those who a decade ago said that socialism was dead, see it now very much alive in Venezuela,” declared the mayor. “It is not that socialism failed, it is that socialism has not come.”

Well, socialism certainly won’t come to Britain as long as Tony Blair is in charge. So far this week, he has outraged the human rights lawyers by attacking the judge-made law that is hampering the fight against terrorism, upset the environmentalists by endorsing a new generation of nuclear power stations, and warned Mr. Chavez bluntly to play by the rules in the international oil trade. Despite the political obituaries that are being written daily, Mr. Blair is not giving up yet. And he remains the biggest single obstacle to the anti-American Left.

That is where the Islamists come in. Figures like Mr. Livingstone are quite unscrupulous enough to make tactical alliances with notorious Islamists, such as Sheikh Qaradawi, whom he has grotesquely compared to Pope John XXIII.

Mr. Qaradawi, for those who do not know him, is the spiritual leader of the Muslim Brotherhood – perhaps the largest and most influential of all Islamist organizations. Hamas is, in effect, the Palestinian branch of the Brotherhood, and Mr. Qaradawi consistently defends the use of suicide bombers against Israel. Of course, Mr. Qaradawi also holds views about women, homosexuals, and infidels, which ought to give a politician such as Mr. Livingstone pause. But he dismissed a coalition of Hindus, Sikhs, Jews, gays, lesbians, and students who documented the sheikh’s views as a Mossad conspiracy to defame Islam.

This outburst was no aberration. As regular readers of this column may recall, the mayor of London has a long record of anti-Semitism, culminating in an unprecedented suspension from office for comparing a Jewish journalist to a Nazi concentration camp guard and then refusing to apologize.

As it happens, Mr. Chavez fits in neatly with the mayor’s prejudices. Last Christmas, the Venezuelan president delivered an openly anti-Semitic rant at a rehabilitation center in Caracas: “The descendants of those who crucified Christ … have taken ownership of the riches of the world, a minority has taken ownership of the gold of the world, the silver, the minerals, water, the good lands, petrol, well, the riches, and they have concentrated the riches in a small number of hands.”

So the anti-American coalition is also an anti-Semitic one – and that is no coincidence. The two ideologies exhibit similar pathologies, appeal to similar constituencies, and are manipulated for similar purposes. They are, in reality, two sides of the same counterfeit coin, as Natan Sharansky has long argued and as I try to analyze in next month’s Commentary magazine.

But what has happened for Great Britain, of all countries, to find its public square polluted by this miasma of prejudice? Readers who are interested should get hold of “Londonistan,” a devastating expose by the British journalist Melanie Phillips, which has just been published in New York by Encounter Books.

I like to think that English notions of decency and fair play are still alive, if dormant. But the spectacle of a Latin American demagogue invited to denounce our most important ally from the municipal heart of the capital makes me see – literally – red.