Jewish organisations are to blame for the community's fractured relationship with the left following Jeremy Corbyn's election as Labour leader, a prominent activist has claimed.
David Rosenberg, a writer and Jewish Socialists' Group member, said the Zionist Federation and Board of Deputies - and the JC - had "lurched further to the right" to attack Mr Corbyn and his supporters.
Speaking at a meeting on Tuesday about the left's relationship with British Jews, Mr Rosenberg said: "They have simultaneously engaged in a demonisation of the left, painting left-wing critics like Jeremy as friends of antisemites or antisemites themselves.
"A small minority of left-wing individuals make it easy for them with crude analysis and some outrageous comments…
"But in meeting rooms and in newspapers, most trade unionists and socialists I encounter argue their case against Israeli policy and Zionism calmly, rationally and convincingly."
The left has become 'useless' at distancing itself from anti-Zionists
The event, at Birkbeck University in central London, was hosted by the Pears Institute for the Study of Antisemitism.
Professor Alan Johnson, of Israel advocacy group Bicom, said: "In some ways today is a springtime for antisemitism and anti-Zionism."
He said the left had become "useless" at disassociating with groups whose "anti-Zionism is vile and murderous".
In order to repair the relationship between Jews and the left, he said an "intellectual firewall" needed to emerge between legitimate criticism of particular Israeli government policies and demonisation of Israel per se. Also speaking were UK Lawyers for Israel's Lesley Klaff and Nadia Valman of Independent Jewish Voices.
An earlier version of this report mistakenly implied that Prof Johnson was calling for a firewall between Jews and the left.
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