As part of the South Bank Literature Festival on July 10 a debate took place between supporters and opponents of what was termed "cultural boycott". The discussion was billed as an event focused on cultural boycotts in general and whether such devices "can be an effective, indeed morally imperative, political strategy". But the organisers clearly intended the occasion to be centred on boycotts targeting Israel. For the motion were the Palestinian activist Omar Barghouti and the poet and psychotherapist Seni Seneviratne. Opposing them were Carol Gould and Jonathan Freedland.

I was not present, but I have read several accounts of what took place, from Carol herself, from JC reporter Marcus Dysch, and from an anonymous blogger who also witnessed what took place. And what took place - what all these accounts agree upon - was not so much a reasoned, respectful discussion than a heated outpouring of personalised verbal venom.

Carol - a celebrated author and producer of TV documentaries - has recalled that at various times during the "debate'" neither she nor Jonathan could speak "because of the loud hysteria of the crowd". Jonathan - one of the UK's leading journalists and broadcasters - was also clearly shocked at the turn of events. As Marcus said: "What really struck me - and seemingly shocked Jonathan too - was how little interest the pro-boycotters had in any form of rational debate… Practically every audience intervention was less question, more a direct attack on him and/or Israel." The audience, Marcus adds, "were vicious, argumentative, rude, and revealed views which were absolutely and utterly entrenched."

That the motion was carried overwhelmingly does not concern me. What does concern me is the reported make-up of the audience. Marcus recalls "familiar faces from the anti-Israel circuit showed up. Piling in one after another were the likes of Tony Greenstein and Deborah Fink." According to Carol, "The audience was comprised of what appeared to be about 150 members of Jews for Justice for Palestinians, Jews for Boycotting Israel and Just Peace UK, Writers for Palestine, PalFest as well as some venomous non-Jews."

In other words, a goodly proportion of this hysterical and offensive audience appears to have been drawn from the ranks of British Jewry. Jews were abusing Jews - in the glare of the media. And these Jews were apparently delighted at the opportunity to be seen to be behaving publicly in this fashion. How are we to explain this troubling psychopathology?

There is nothing new about Jewish opposition to Zionism

There is nothing new about Jewish opposition to Zionism. Chief Rabbi Hermann Adler (he of the dog-collar and gaiters) was one of the Protestrabbiner who denounced the first Zionist Congress. As a member of Lloyd George's cabinet Edwin Montagu did his damnedest to sabotage the Balfour Declaration. Claude Montefiore, one of the founders of Liberal Judaism, blamed Zionism for the rise of Hitler. In propagating their anti-Zionist creed these notables could justly claim that they were voicing the widely held anxiety that any assertion of a distinct Jewish nationality could imperil the security of Jews in the diaspora. After the Holocaust these fears subsided - to some extent - but they were kept alive through the antics of the Jewish Fellowship (1947-48). The unmistakeable signs now are that they have been reignited as a by-product of events in the Middle East.

In his recently-published monograph Jewish Identity & Palestinian Rights, the Irish-Jewish academic Dr David Landy, who teaches at Lancaster University, examines diaspora Jewish opposition to the State of Israel. By his own admission Dr Landy is "active in the Palestine Solidarity Movement" and neither Jonathan Freedland nor Carol Gould will be surprised to learn that the book itself boasts praise from Omar Barghouti as well as (for good measure, I assume) Ilan Pappé.

To derive intellectual benefit from reading this work one has to ignore Dr Landy's naive acceptance of the customary charges levelled against the Jewish state (ethnic cleansing, apartheid, etc) and concentrate instead on his dissection of contemporary Jewish anti-Zionism on both sides of the Atlantic. For many such Jews, alienated from contact with mainstream Jewish communities, joining a Jewish-led pro-Palestinian movement appears to bolster their self-respect and help them reconnect (bizarrely, I know) with the Jewish world - or at least with a Jewish world. In this sense their anger with Jews who support Israel is best viewed as a form of ethnic identification and an assertion of their uncritical belief in the benefits of a diasporic existence.

We ought - in other words - to feel profoundly sorry for them.