Momentum founder Jon Lansman today admitted there is a problem with anti-semitism within the Labour Party and that it “must be dealt with”.
The ardent Corbyn supporter, who is Jewish, told the BBC’s Andrew Marr Show the issue was on the rise across society as a whole.
“It would be extremely surprising if it wasn’t also present in the Labour Party.”
Lansman said he was “so pleased” a motion to take more robust action against those who engaged in discriminatory behaviour had been put forward and accepted at Labour’s party conference in Brighton last week.
When asked about other high-profile backers of Jeremy Corbyn - including Unite general secretary Len McCluskey and film director Ken Loach - claiming anti-semitism is not a big problem, he said: “You have to be a Jew to actually experience anti-semitism. I have experienced anti-semitism, my children who are only half Jewish have experienced it.
“I know there is a problem with anti-semitism and it has to be dealt with.”
He added: “It incredible important to me as a Jew. My reading as a child about the oppression and victimisation of Jews through the centuries...is what defined my policies.”
Lansman described himself as “a radical socialist” and said Momentum had thousands of activists trained up in marginal seats across the country to campaign against sitting Tory MPs.
Asked why Momentum had moved to block a vote on Brexit at Labour conference, he said: “We had lots of debate about Brexit, with speeches by Keir Starmer and Emily Thornberry, and outside conference there was lots of debate on the fringes, including at events we organised.
“Brexit is not the only thing that is important. There are other policies we wanted a discussion about; the NHS, housing, about railways, about social care for the elderly. There are lots of things that are important to discuss.”