Jon Lansman, the founder of Momentum, has insisted that Jeremy Corbyn should go on a training course to increase his awareness of antisemitism.

Speaking on the BBC’s Victoria Derbyshire show Mr Lansman said he believed all the members of the party’s National Executive and the National Constitution Committee should attend such a course.

Asked by Ms Derbyshire whether he included the party leader, Mr Lansman replied: “I think we all should. I think everybody who deals on the National Executive of the Labour Party, from investigators to members of the National Executive and the National Constitution Committee who is the, if you like, final judicial body, needs to do that."

Ms Derbyshire said: “That is extraordinary, Mr Lansman, what you just said. The leader of the Labour Party, you believe needs to go on a training and education programme in order to educate himself about antisemitism.”

Earlier Mr Lansman had spoken of what he called the problem of “unconscious bias” which he said affected all organisations, including the Labour Party – and suggested the need for training courses to re-educate people over matters such as antisemitism and sexual abuse.

Mr Lansman was joined on the programme by Jonathan Goldstein, chair of the Jewish Leadership Council.

Mr Goldstein criticised Mr Corbyn’s decision to attend a Passover seder organised by the Jewdas group.

He said “it speaks volumes” that if the Labour leader claimed he wished to build bridges with the mainstream Jewish community that his first act was to sit down with a group who were openly hostile to it.