Pete Willsman, the controversial member of Labour’s ruling body who called Jews "Trump fanatics", has admitted threatening to “do in” Jon Lansman, the Jewish founder of left-wing campaign group Momentum.

Pete Willsman, whose rant about Jews was exposed by the JC last July, was revealed to have threatened Mr Lansman - who masterminded Mr Corbyn’s Labour leadership campaign - in leaked emails published in the Daily Mail.

In the messages, Mr Lansman called Mr Willsman a “hateful, embarrassing dictator and crank.”

Mr Lansman said Mr Willsman “waited two hours outside a room in which I was engaging in a telephone conference to threaten me when I emerged.”

He said Mr Willsman’s “precise words” were “’I am going to do you in’”

Mr Lansman told the Daily Mail: “Comrade Willsman is consumed with hatred of me.

“He has become an embarrassment to the Left and a serious risk to the reputation of Jeremy Corbyn and the Labour Party. His NEC contributions are cranky.”

In the emails, Mr Lansman, who has stressed Labour's problem with antisemitism needs dealing with, described Mr Willsman as a “stupid liar, belligerent and unpleasant – and is losing it.”

Mr Willsman admitted that he said he would “do in” Mr Lansman.

He told the Daily Mail: “It is daft to suggest I meant I was going to do him in physically. I meant it purely in the political sense.”

Mr Willsman told reporters that he had offered to end the fued with Mr Lansman if he was given an apology, but Mr Lansman declined.

He said: “He just laughed and walked away so I responded rather irritably.”

Last July, the JC published a recording of Mr Willsman speaking at a meeting of Labour's National Executive Committee, just after 68 rabbis from all denominations signed a public letter condemning Labour antisemitism.

The recording revealed Mr Willsman shouted: “Some of these people in the Jewish community support Trump. They are Trump fanatics and all the rest of it…

"So I am not going to be lectured to by Trump fanatics making up duff information without any evidence at all.

“So I think we should ask the 70 rabbis where is your evidence of severe and widespread antisemitism in this Party?’”

The JC's story prompted Momentum to withdraw its endorsement of Mr Willsman in the NEC elections in September, though he was still re-elected to it. 

Mr Willsman continued to get support from Labour MP Chris Williamson, whom Labour has suspended, over his approach to the party's antisemitism crisis.