A two-hour debate hosted by Momentum – asking whether there is antisemitism in the Labour party – grew heated on Sunday evening of the Labour party’s annual conference.

The packed out room, at the campaign movement’s fringe called The World Transformed, was warned beforehand to avoid “bitter incivility of discourse”. Which, translated from the language of Labour conference, means: “Don’t say anything dreadful.”

Jackie Walker, the vice-chair of Momentum, argued that antisemitism claims have been “exaggerated for political purposes”, and “the most fundamental aim of such allegations, I suggest, is to undermine Jeremy Corbyn”, and “silence” his supporters.

She claimed that there is “little if any hard evidence” that Labour has a problem with antisemitism, and blamed a “rabidly, anxiously anti-Corbyn” media for using antisemitism claims as a “weapon of political mass destruction”.

“Being offended is not the same as experiencing racism,” Walker added. “Claims of racism have been weaponised . . . Both the chair and the vice-chair [referring to herself] of Momentum are Jewish, and many leading members of Momentum are Jewish.”

(Later an audience member picked up on this theme perhaps a little too zealously. “Trotsky the Jew? Lenin the Jew? What about Zinoviev? What about Kamenev?” he cried, concluding that therefore claims of left-wing antisemitism are “nonsense”.)

Jeremy Newmark, head of the Jewish Labour Movement, clashed with Walker, accusing her of having “perpetuated” the “antisemitic myth” of slave trade collusion (referring to a comment she made on Facebook for which she was briefly suspended from Labour).

She hit back by saying she was “disappointed” in his comment, and had “simply repeated the defamation of his friends in the Jewish Chronicle”, accusing them of racism towards her as a black woman.

Newmark lamented that, “the relationship between our community and the Labour Party has deteriorated”, and “it pains me that a once historic natural alliance [should] dissipate, dilute and disappear”.

He warned those who “want to criticise someone for over-egging” the issue of antisemitism in the party should look no further than Jeremy Corbyn, who called for Shami Chakrabarti’s inquiry into the subject. “Perhaps you should criticise him.”

It was a tense exchange, which elicited gasps and heckles from the audience. But perhaps less predictable was the description of the Labour antisemitism row as a “monstrous soufflé” by Professor Jonathan Rosenhead, an LSE academic involved in boycotting Israeli universities.

He called it “a monstrous soufflé of moral panic being whipped up”, and warned the audience: “We need to ask about this soufflé”.

“Who are the cooks? Where’s the kitchen? What are the implements?” he asked, before the killer rhetorical question: “Why has this soufflé been cooked?”

Update

Momentum appears to be distancing itself from Walker’s comments at this event. A spokesperson emphasises that the group hosted the discussion on antisemitism in light of the Chakrabarti inquiry “because it is absolutely crucial that our movement understands how antisemitism manifests itself, and works to stamp it out in society as a whole as well as in our party”.