Local organisers have performed a U-turn after the JC, as well as other media outlets, was blocked from an event featuring John McDonnell and Jenny Manson, the co-chair of Jewish Voice for Labour (JVL).

The Shadow Chancellor agreed to take part in a head-to-head conversation with Ms Manson on Thursday evening at an event organised by the Barnet Momentum group at the Clayton Crown Hotel in Cricklewood.

It has been interpreted by many as a signal of his support for Ms Manson’s bid to become an MP in the Finchley and Golders Green constituency.

Mr McDonnell has said since that she has his support in seeking the Labour nomination to contest the seat.

The JC received an email on Wednesday evening from Carlos Soto, a member of “Jenny’s Campaign Team”, who cited a “lack of media accreditation and underpayment” as reasons for the decision.

Attendees were asked to make a monetary donation to Ms Manson’s campaign. This newspaper donated £1.

It is understood that the Jewish News was also blocked from the event, as were David Collier and Euan Philipps, two prominent campaigners against antisemitism. Organisers have since confirmed journalists will be admitted.

Mr Soto said: “I cannot comment on individual cases. The JC was rejected because the journalist did not apply for press accreditation and he did not make the correct donation of £8.”

He said people who made a donation below £8 had their tickets rejected or "were given the opportunity to make up the difference".

It has also emerged that a group of young Labour activists from Barnet wrote to Mr McDonnell last month to express concern over his apparent endorsement of Ms Manson.

They cited Ms Manson’s alleged support for Tony Greenstein, an anti-Israel activist who has been suspended from the Labour Party, and her “toleration of antisemitism”, urging the Shadow Chancellor to “disavow support for Jenny Manson’s candidacy at the earliest opportunity”.

Mr McDonnell said: "Jenny is a good friend and I am fulfilling a longstanding commitment I gave her to offer her my support in seeking selection as a candidate."