The JC understands that the Equality and Human Rights Commission will announce an investigation into the Labour Party on Thursday.

In November, the Jewish Labour Movement (JLM), which voted on Wednesday to remain affiliated to Labour for at least another month, submitted a dossier of Labour antisemitism to the Equalities and Human Rights Commission.

It asked the EHRC to investigate the allegation that the Labour Party is institutionally antisemitic.

The Campaign Against Antisemitism also submitted a dossier earlier last year.

According to a Labour source, the party has known about the EHRC inquiry for some weeks and has been negotiating terms of reference.

In a statement on Wednesday, the JLM said: "We did not take that decision lightly.

"After years of anti-Jewish racism experienced by our members, and a long pattern of denial, obfuscation and inaction by those with the power and ability to do something about it, we felt there was little choice but to secure a fully independent inquiry, not encumbered by corrupted internal practices.

"Everything that has happened in the months since our referral supports our view that the Labour Party is now institutionally antisemitic...This evening Jewish Labour members made clear that we will not unconditionally stand by whilst we are treated with such intolerance and contempt."

In October, the JC revealed how a new Antisemitism Monitoring Centre set up by the JLM to record and process complaints relating to Jew-hate within Jeremy Corbyn’s Labour Party had received over 600 submissions — just a week after it was launched.

An email sent by JLM to its 2,000 members suggested there was a urgent need for the service because Labour had allowed complaints of antisemitism to be “dismissed when reported, obfuscated when they entered the national press, and dragged on because that was politically easier”.