Jeremy Corbyn warned antisemitism could stop Labour winning power after Holocaust denial row hits conference

Labour cannot win power while Jewish voters shun the party over antisemitism, a defeated candidate has warned, as allegations of Holocaust denial tarnished the conference.

Mike Katz warned Jeremy Corbyn of many “difficult conversations” on the doorstep with Jewish people who were turning their backs on Labour because of the perception of an antisemitism stain.

He spoke out as Tom Watson, Labour’s deputy leader, vowed the party would investigate a speaker in Brighton who said people should be allowed to question whether the Holocaust took place.

Mr Watson said he was disgusted the party gave a platform to Israeli-American author Miko Peled, who told a conference fringe event there should be “no limits on the discussion”.

“This is about free speech, the freedom to criticise and to discuss every issue, whether it’s the Holocaust: yes or no, Palestine, the liberation, the whole spectrum,” Mr Peled is reported to have said.

Jeremy Corbyn was forced to reject accusations that Labour was now the “nasty party”, insisting all antisemitic language was “completely at odds with the beliefs of this party”.

The controversy then broke out on the conference floor, when the Jewish Labour Movement (JLM) was accused of “running to the Daily Mail and Daily Telegraph with stories”.

A furious JLM said the attack – by Naomi Wimborne-Idrissi, who chaired the fringe event where Mr Peled made his remarks – amounted to an “antisemitic trope" and demanded action.

The row overshadowed the conference preparing to agree a rule change to explicitly outlaw antisemitism by party members, rather than simply any actions deemed to be “prejudicial”.

In his speech, Mr Katz warned delegates of the response from Jewish voters when he lost narrowly to the Conservatives in Hendon, north London, at the June election.

“I'd be lying if I said my team and I didn't have plenty of difficult conversations on the doorstep with concerned Jewish voters who'd always backed Labour in the past but weren't sure now,” the JLM vice-chairman said.

“We need to win seats like Hendon, Finchley and Golders Green, Chipping Barnet, Harrow East and seats across north London and around the country if we're to rid this country of the awful Tory Government.

“So repairing the once-strong relationship between our party and the Jewish community, where we share so many shared values, is a political imperative as well as a moral one.”

Philip Cohen, a councillor from neighbouring Barnet, also warned many Labour voters in Barnet turned away from the party for failing to take antisemitism seriously.

Asked about Mr Peled’s comments, on ITV’s Good Morning Britain, Mr Watson said: “It is nothing to do with the official Labour party conference.

“And if there was Holocaust denial there, these people have no right to be in the Labour party, and if they are they should be expelled.”

Labour’s conference organising committee would investigate how the author had been given a seat on a panel at the event, he added.

The current Labour party rules say: “No member of the party shall engage in conduct which in the opinion of the NEC is prejudicial.”

The amendment, backed by the JLM, adds a commitment to act on “incidents involving racism, antisemitism, Islamophobia or otherwise racist language, sentiments, stereotypes or actions, sexual harrassment, bullying or any form of intimidation”.