Momentum chair Jon Lansman, a key ally of Jeremy Corbyn, has admitted there is a "major problem" with antisemitism within Labour that is underestimated by party figures.

The influential left-winger, who sits on Labour's ruling National Executive Committee (NEC), claimed there is a "much larger number of people with hardcore antisemitic opinions" than first thought.

And he suggested conspiracy theorists were "more of a problem" in the Labour Party than the Conservatives.

Mr Lansman, whose Momentum group grew out of Mr Corbyn's initial Labour leadership campaign, spoke of a "widespread problem" with anti-Jewish hate following the resignations of nine Labour MPs from the party.

Many have attacked Mr Corbyn's failure to deal with antisemitism, with some even branding Labour an "institutionally antisemitic" party.


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Mr Lansman, who is Jewish, disagreed with that description but told BBC Radio 4's Today programme: "I do think we have a major problem and it always seems to me that we underestimate the scale of it.

"I think it is a widespread problem. It's now obvious we have a much larger number of people with hardcore antisemitic opinions which, unfortunately, is polluting the atmosphere in a lot of constituency parties and, in particular, online.

"We have to deal with those people and I think it's a responsibility of everyone in the Labour Party, from the top to the bottom, to report cases."

Mr Lansman called on Labour to be more "proactive in going out and seeking cases" of antisemitism within the party, but added the NEC has "cleared the backlog" of complaints and a disciplinary body had been "doubled" in size.

Asked why antisemitism has been a persistent complaint under Mr Corbyn's leadership of Labour since 2015, Mr Lansman said: "One aspect of the problem is the party trebled in size.

"We took in 300,000 or more new members and amongst those members are members who are attracted towards conspiracy theories."

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Mr Lansman suggested Facebook "can become an arena in which a minority with hardcore antisemitic views can infect" various groups.

He added: "I think there are probably conspiracy theorists in many parts of the political spectrum. I don't think that's exclusive to the Labour Party.

"The Tory party is a small party and an elderly party and I think the role of social media in fomenting and spreading the poison is therefore more of a problem in the Labour Party."

Mr Lansman also defended Mr Corbyn amid the renewed scrutiny of antisemitism allegations within Labour.

"Jeremy Corbyn has been an anti-racism campaigner all his life and I've known him for decades," he said.

"I do absolutely believe in his commitment to eradicate that."

In a recent interview with Sky News, Mr Corbyn insisted Labour does not accept "antisemitism in any form" in the party.

However, he resisted calls from Labour shadow chancellor John McDonnell for the party to be "quicker" in dealing with allegations.

"We do it as quickly as we can but there has to be fairness involved with it," Mr Corbyn said.

Mr Lansman's comments came after Labour deputy leader Tom Watson issued a direct challenge to Mr Corbyn over antisemitism, Brexit and the future of the party.

In a blogpost on Sunday night, Mr Watson confirmed he has received 50 complaints about antisemitism that he has passed on to Mr Corbyn and asked him to "take the personal lead on examining these cases".

Mr Watson is also forming a group of centrist Labour MPs - those "who believe in the party's social democratic tradition" - to develop policies.

And, with Mr Corbyn still resisting pressure from within Labour to formally back a second EU referendum, Mr Watson said he would "likely" join a People's Vote campaign rally next month if Prime Minister Theresa May doesn't move towards Labour's position on Brexit over the next three weeks.