Labour leadership contest: Former leader Ed Miliband urges party members and supporters to sack Jeremy Corbyn

Latest twist in party’s long-running internal war comes as leader accuses his deputy of ‘peddling baseless conspiracy theories’ over claims young supporters are are being manipulated by hard left activists

Jeremy Corbyn has accused his deputy, Tom Watson, of orchestrating an anti-Corbyn ‘Project Fear’, and Mr Corbyn’s predecessor, Ed Miliband, has urged party members and supporters to vote to sack Mr Corbyn, in the latest twists in Labour’s long-running internal war.

The Labour leader claimed that his deputy was “peddling baseless conspiracy theories” after an interview in which Mr Watson alleged that young activists who back Mr Corbyn are being manipulated by experienced Marxist ideologues who are not interested in seeing a Labour government elected.

Mr Corbyn is also angry because Mr Watson persuaded members of Labour’s national executive to lodge an appeal against a high court ruling that would allow 130,000 newly recruited party members an automatic right to vote in the current leadership contest between Mr Corbyn and his challenger, Owen Smith.

It is assumed that the majority of new members who flocked to join the party after the 23 June referendum intended to use their votes to re-elect Mr Corbyn as leader. If true, the outcome of the leadership race could depend on whether those new members are all entitled to vote.

Mr Smith already has an uphill task winning over Labour party members and supporters, more than 250,000 of whom voted for Mr Corbyn less than a year ago. It is not clear how many will have their minds changed by the announcement that Mr Miliband is backing Mr Smith. The former party leader is emailing all party members urging them to vote for the challenger as someone who believes in a more equal society and could “unite our party and make us a serious alternative government".

In the 1980s, the Labour Party expelled hundreds of members of groups who followed the doctrines of the Bolshevik leader Leon Trotsky. Mr Corbyn opposed the expulsions at the time and has often shared platforms with Trotskyists and others to the left of the Labour Party.

But Mr Watson supported the expulsions at the time, and believes that Trotskyists are using Mr Corbyn’s rise as an opportunity to regain a hold within the party.

He told The Guardian: “There are some old hands twisting young arms in this process, and I’m under no illusions about what’s going on. They are caucusing and factionalising and putting pressure where they can, and that’s how Trotsky entryists operate.

“Sooner or later, that always ends up in disaster. It always ends up destroying the institutions that are vulnerable, unless you deal with it.”

A statement from the Corbyn leadership campaign accused him of “sadly using the Owen Smith campaign's 'Project Fear' approach".

It added: “Labour members want a politics of hope, reflecting the fact that our party's membership has grown to become the largest of any left of centre party in Europe under the leadership of Jeremy Corbyn.

“We regret that Tom Watson also forced through the decision yesterday at Labour's NEC meeting to challenge the court judgement to restore the right to vote in the leadership election.

“Rather than patronising members and peddling baseless conspiracy theories about ‘Trotsky entryists’, he should be working with Jeremy to unite our party so that we can get back to campaigning to dislodge this Tory Government, and help elect a Labour government in its place.”

Mr Watson responded by saying that he could not understand why the Corbyn camp should be so ”intemperate". He said: “In my interview with The Guardian I made it clear that many members of Momentum are motivated by a desire to see political change and build a more equal society.

“John McDonnell has consistently made it clear that everyone in our party must be free to express their opinion and be heard respectfully without fear of being shouted down, which is why I simply don't believe he approved these intemperate words from Jeremy's campaign.”