More than 2,000 supporters of Jeremy Corbyn have backed an open letter suggesting a Jewish-organised protest against antisemitism in the Labour Party was the work of a “very powerful special interest group”.

The open letter, posted to Mr Corbyn, claimed the organisers of Monday’s demonstration had used their “immense strength” to “employ the full might of the BBC” in order to launch an “onslaught” against the Labour leader.

The event was organised by Jewish community groups the Board of Deputies and the Jewish Leadership Council.

The letter claims the organisers had sought to use their “history” and ”influence” to “dictate who the rest of us can vote for or how we vote”.

It comes as Mr Corbyn battles to respond to allegations he has failed to adequately address antisemitism among his supporters.

The letter was posted on the “We Support Jeremy Corbyn” Facebook group and was “liked” by more than 2,000 of the group’s followers. Almost 1,000 commented asking for their names to be added to the text.

Coming the day after Monday’s protest, it states: “Yesterday we witnessed the full onslaught of a very powerful special interest group mobilising its apparent, immense strength against you.

The letter claimed the protest organisers had used their ‘influence’ and ‘history’ to dictate how people vote

“It is clear this group can employ the full might of the BBC to make sure its voice is heard very loudly and clearly. It is a shame not every special interest group can get the same coverage.”

It adds: “But, and it is a very big BUT, we live in a democracy, a one member one vote democracy and no special interest group, regardless of their history or influence, can be allowed to dictate who the rest of us can vote for or how we vote.”

We witnessed the full onslaught of a very powerful special interest group mobilising its apparent, immense strength against you Open letter in support of Jeremy Corbyn

It was posted by a user named Frances Naggs, who said they were a Labour Party member in the Staffordshire Moorlands constituency. The Independent has approached the leader's office for a comment.

The news came as an ally of Mr Corbyn was forced to resign as chair of a key Labour disciplinary panel after a leaked email revealed she had argued that a council candidate who claimed the Holocaust was a “hoax” should not be suspended from the party.

Labour sources said Mr Corbyn had asked Christine Shawcroft to step down as chair of the Disputes Panel, which investigates allegations of antisemitism and other offences, after her email was leaked to The Times.

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Earlier on Thursday the leaders of the Board of Deputies and Jewish Leadership Council refused Mr Corbyn’s request for an “urgent meeting” unless he agrees to meet a number of conditions, including appointing an independent ombudsman and publicly condemning abuse of Labour MPs who attended Monday’s protest.

In an attempt to quell rising anger about antisemitism in Labour, Mr Corbyn wrote to the two groups on Monday admitting that “anti-Semitic attitudes have surfaced more often in our ranks in recent years” and accepting that the party ”has been too slow in processing some of the cases that have emerged”.

Requesting an “urgent meeting” to discuss the issue, he said: “I recognise that anti-Semitism has surfaced within the Labour Party, and has too often been dismissed as simply a matter of a few bad apples.

“This has caused pain and hurt to Jewish members of our party and to the wider Jewish community in Britain.

“I am sincerely sorry for the pain which has been caused, and pledge to redouble my efforts to bring this anxiety to an end.”