When I was 16, I went to toil in a kibbutz in Israel for a few months, imagining myself as a Hebraic warrior, sweatily harvesting oranges with fecund Israeli girls in groves blossoming with Jewish ingenuity amid the once-sterile Negev Desert. I actually found myself making plastic toilets. This was not good for my Jewish self-image. David Ben-Gurion, Israel's founder, foresaw that statehood meant Jewish intellectuals, but also truck drivers and criminals. But he never mentioned loo-makers. From the shtetls of Lodz to Starbucks in Manhattan, even our comic geniuses - Sholom Aleichem, Woody Allen or Jerry Seinfeld, had not invented the Jewish toilet-maker. So here I was: a new character in our ancient canon of self-mockery, the humour that makes our tragedies bearable, our successes ridiculous. My favourite example: my witty great-uncle being asked his age at a funeral. "Ninety-two," he said. "Hardly worth going home, is it?"
At the toilet factory, I worked a sealing gun joining the pipes. Whenever I tried to fuse them, however, one would fly off, spinning around the factory and sending workers ducking for cover. I was such a klutz, that I was called before the Boss, a septuagenarian cockney who had fought Mosley's fascists in the 1930s. He was contemptuous of me not only for my lack of toilet-training (as it were) but also because I was a public-school, "gilt-edged Jewish Monte-Fauntleroy" - by which he meant the Montefiores had helped build Jewish settlements in Ottoman Palestine, but never deigned to live there. I retorted that my mother's family were tough immigrants from Lithuania, Poland and Russia. The Boss laughed: "That's being a Jew: Heinz has 57 varieties."
This Heinzian principle of Juda-ism has been overshadowed by the contemporary image of Israel - and by the frenzied anti-Zionist, anti-American circus of bizarre conspiracy theories that present Jews as a single political "cabal" rather than the world's most diverse diaspora, a wealth of religious, cultural and racial communities, separate from Israel or America.
The diaspora tells its stories in some newly republished literature - remarkable voices such as Joseph Roth and Isaac Babel: as well as Isaac Bashevis Singer, Saul Bellow and Philip Roth. In Britain, Howard Jacobson has just published an Anglo-Jewish comedy, The Making of Henry, which shows the Jewish experience here is as laden with absurd angst as that of Bellow or Singer.
I learned how small the Jewish community is in Britain when I was at Cambridge, having an affair with a girl who had no idea I was Jewish. One day, in bed, it slipped out. Eyes widening as if I had horns and fangs, she explained that her father had warned her that she might "meet Jews" at Cambridge, but she must beware of this "amoral but diabolically clever sect". Now, she mused, with an erotic shiver, "The first one I meet is in my bed."
Being an English Jew is very different from being an American Jew. American Jews can never quite understand the insecurities of being a European Jew, for the 5.8 million American Jews feel totally secure. (Though it should be noted that in the US, there are still co-ops in uptown NYC, clubs in Miami, where Jews are inadmissible.) Here in Britain, we are only 275,000 out of 60 million. Most parts of Britain have no Jews at all. I constantly meet educated Brits who have never met a Jew. Such people can never quite believe it: "You're not, are you? Oh, you really are. Great! I've always thought you're a very clever people."
You might say that only a Jew could possibly take this acclamation of cleverness as an insult. Being a Jew is all about living on several levels, listening on different frequencies, deciphering codes. Even in England. But I have to say that there is not a single day when I do not thank God that I was born a Jew in England, this tolerant, quirky, flexible land that has embraced Indians, Pakistanis, African Caribbeans as it embraced Jews. It is typical that, when my wife converted to Judaism, I couldn't have been more welcomed into her family. Ultimately, since our Cromwellian return to this island, the Anglo-Jewish experience has been positive. First, there were the Sephardic (Arab-Mediterranean) Jews, like my own family, the Sebags of Essaouira, Morocco. In the 1880s, the Ashkenazim arrived, refugees from tsarist pogroms. These included my mother's family, poor but learned, descended from 33 generations of rabbis. My mother's Lithuanian-Russian ancestors have not done badly: they spawned two Lord Chief Justices (including the present one) and (crazy but true) Gwyneth Paltrow. (Yes, the ultimate ivory-skinned blonde shiksa who, according to a surreal Jewish Chronicle "exclusive", is - like me - descended from the Paltrowiches of Nizhniy Novgorod.)
Anti-Semitism here was subtle. Yet those Sephardic ancestors felt they had to work particularly hard and behave especially well: "Our race can do anything but fail," wrote a Montefiore to Benjamin Disraeli. Prejudice was part of upper-class culture - and literature, too: see John Buchan's Jewish villains, George du Maurier's wicked Svengali, or Anthony Trollope's grotesque financier Augustus Melmotte and Sephardic adventurer Ferdinand Lopez.
Although between the wars, Arthur Balfour and Winston Churchill fostered Zionism and a Jew was appointed Viceroy of India, there were also Oswald and Diana Mosley and those mandarins who complained during the 1930s of "wailing Jews" making out as if the Nazis wanted to kill them all. When Anthony Julius, lawyer to the late Princess of Wales, recently published a book about T S Eliot (whose wonderful poetry gave literary anti-Semitism a good name), he argued that anti-Semitic prejudice was sometimes serious, but often harmless. It "encompassed drawing-room condescensions and forest shootings", but "the drawing-room anti-Semite" is "not a murderer", just an "anti-Semite".
Yet something has changed about the European attitude to Jewishness. One feels it everywhere: we have moved, as it were, from the world of Howard Jacobson back to Franz Kafka. This is connected to Israel, America, 9/11 and Iraq. For more than a decade now, Israel has been the fashionable bete noire of the chattering classes. The response to Israel in the European media, particularly the BBC and the Guardian, has long been prejudiced, disproportionate, vicious often fictitious.
A typical case of the media's mendacity on Israel was the invented coverage of the Jenin "massacre" (not) by British news organisations, which were so anti-Israel that they popularised an event that they could not have witnessed, because it had not happened. They never apologised - because any Israeli "atrocity" is seen to illustrate a greater truth. Another example was the Israeli assassination of the man whom the BBC called Hamas's "spiritual leader": Sheikh Ahmed Yassin was actually a terrorist boss, about as "spiritual" as Osama Bin Laden.
Yet, in the British media, every Israeli sin is amplified, while those of the Arab world are ignored. The million dead of the Iran-Iraq war, Saddam Hussein's 300,000 victims, thousands more massacred in Chechnya, the Arab militias killing black Sudanese, the torturing Middle Eastern tyrannies are ignored - but in Britain, every Palestinian death is reported like a sacred rite. Our media conceal the venom directed at Israel by Arab clerics, television and the internet, presenting Israeli complaints as propaganda. The Middle East commentator Tom Gross revealed in the National Review that when the "moderate" Saudi cleric Sheikh Abdur-Rahman al-Sudais visited Britain this month, the BBC hailed him as a brave worker for "community cohesion". Yet his Friday sermons call for Jews - "scum of the human race, rats of the world" - to be "annihilated".
It is not anti-Semitic to criticise Israel. Many of its policies are clumsy, self-defeating, wrong. I am against most of the settlements, against the razing of Palestinian houses. Israel will lose its soul if it uses citizen-soldiers to skirmish through Rafah or Hebron for much longer. I want a Palestinian state; I care deeply about the humiliation and deaths of Palestinians. If criticisms against Israel were based purely on its political faults, no one could complain. Yet, since the first intifada, Israel's critics use hysteria and unreality, holding Israel to standards to which Britain, for one, could never aspire. A veteran MP, Gerald Kaufman, regularly attacks Israel in attention-seeking missives billed as "Well-known British Jew attacks Israel", when they should be headlined: "British Jew well known only for attacking Israel attacks Israel again!"
Kaufman provides Jewish cover for more dangerous people. The first head of the hydra-like monster of medieval anti-Semitic conspiracy theories was the implied parallel between Israeli treatment of Palestinians and Nazis' treatment of the Jews. This is a de facto cousin of Holocaust denial, as it diminishes and trivialises what really happened then. Since the second intifada started, 2,000 Palestinians and 1,000 Israelis have died - an appalling loss of life, but hardly a genocide. This couples with sympathy for anti-Israel suicide bombers: Israeli deeds are disgusting, those of Palestinian terrorists permissible, because of their victimhood.
Since 9/11 and Iraq, a millenarian cauldron of old-fashioned anti-Semitic conspiracy theories claims that secretive Jews (the wicked "neo-cons") are controlling Bush, Blair and the media, and even arranged 9/11. Anti-Americanism, anti-Zionism and anti-Semitism have become interchangeable.
The conspiracy fever sounds like something out of that notorious forgery, the Protocols of the Elders of Zion, mixed with the medieval blood libel about the drinking of Christian children's blood. This rubbish seeps over the internet from the Arab media, where feverish anti-Semitism is the norm, to insane US/UK websites. The message: from Iraq to 9/11, it's the Jews wot did it.
Even respectable commentators are at it. Tam Dalyell MP last year said that Tony Blair was "unduly influenced by a cabal of Jewish advisers". After al-Qaeda's Madrid bombings, left-wing commentators argued that the Zionist state was the real source of terrorism. (Yet Israel is the leading Islamist grievance solely in the western media: a glance at jihadist websites actually shows Israel is mentioned much less often than Chechnya, Kashmir, Saudi Arabia and Iraq.) The liberal historian Anthony Sampson blames the turmoil in Iraq on a "neoconservative cabal and the Israeli government". Whatever he actually meant, "cabal" has become a code word, a shibboleth. (Always a "cabal". What would Charles II's Clifford, Ashley, Buckingham, Arlington, Lauderdale make of this? Or were they really Cliffordstein, Ashleichem, the Duke of Buckinghamowitz, Arlingtonbaum and Lauderschnigelglas?)
Conspiracies are founded on coincidence and fantastical connections. Obviously there is no cabal. There were more Jews in Bill Clinton's administration than there are in Bush's; most American Jews are Democrats. Bush's Iraq policy is actually led by Donald Rumsfeld (of German ancestry) and two African Americans, Condoleezza Rice and Colin Powell. (Ever read about the "African American cabal"? Hardly.) This Judification of US policy resembles Goebbels's campaigns against "the Jew Roosevelt". Besides, if the media were really controlled by Jews, they would not continually run anti-Israeli stories. Or covers such as the New Statesman's own "Kosher conspiracy", published in January 2002: illustrated with a brazen caricature, it suggested a London-Jewish conspiracy of arms dealers and press barons, then concluded that no such coven existed.
A part of this is a refusal to analyse what really happened to the Oslo land-for-peace accords. Premier Ehud Barak offered Chairman Yasser Arafat a viable West Bank-and-Gaza state. Arafat turned it down. The Palestinians returned to terrorist tactics; Israelis recalled the old warhorse Ariel Sharon. Both sides have done atrocious things to each other and been ill-served by their leaders. But it is Hamas-PLO that has needlessly resuscitated Sharon's career, destroyed Israel's peace party, sunk its own people into a quagmire of suicide, war, corruption, poverty and humiliation.
When Israel offered to do what everyone has wanted it to do since 1967 - withdraw from Gaza - the reaction to the initiative was as if Sharon had proposed the execution of every first-born in Araby. Yet Sharon's ruthlessness has almost decapitated Hamas, and certainly slowed the suicide bombings. Indeed, as a result of his policies, there are signs that the intifada is drawing to an end.
Today's conspiracy fever is based on fear, expressed in a millenarian yearning for answers in an uncertain, post-cold war world. Fear of Islamist terrorism leads some to think that if the suicide bombers of al-Qaeda/Hamas are so fanatically strong, they must be just.
In blaming Jewish-American neo-cons and in longing to appease the terrorists, the bien-pensants purveyors of these conspiracies will not heal Islamist grievances. For such grievances are about western power, modernity and freedom. Islamist terrorists visualise "Jews" as perhaps a weak link in our western civilisation, but an essential part of our society. Those who swallow conspiracy theories miss the point. For al-Qaeda maniacs, we are all Jews.
This month, arsonists attacked two more synagogues in north London; more than one hundred synagogues have been desecrated since 2000. This, in a time of prosperity: what would happen in a time of instability if these cod conspiracies became accepted political discourse?
Until 9/11, Anglo-Jewry had become accustomed to prejudiced coverage of Israel. But if you were not a Zionist, as many Jews are not, you did not need to worry. Since 9/11, and particularly post-Iraq, we have witnessed a sea change. It is as if, in the mythical scale of 9/11, al-Qaeda had unlocked a forgotten cultural capsule of anti-Semitic myths, sealed and forgotten since the Nazis, the Black Hundreds and the medieval blood libels. Just words? But words matter in a violent world. This weird and scary nonsense is an international phenomenon, not a British one. Despite it, Britain retains the easygoing tolerance and pragmatism, the sources of her greatness. It is still better to be a Jew in England than anywhere else.
Stalin: the court of the Red Tsar by Simon Sebag Montefiore, which won the History Book of the Year prize at the British Book Awards, is out in paperback from Phoenix (£9.99)