Jeremy Corbyn confessed to a top ally he never wanted to be Labour leader it was claimed.

Jon Lansman, who set up the Momentum campaign group credited with helping Corbyn win the leadership, revealed that the Islington MP had hoped he’d lose.

Lansman recalled Mr Corbyn’s response to securing a slot on the ballot paper in 2015: “He said you better make f***ing sure I don’t get elected.”

The Labour leader, who until his election had been a backbencher for his entire parliamentary career, only made the shortlist in the nick of time by gaining the nominations of 35 MPs - many of whom did not go on to support him.

A Labour source told the Daily Mirror Corbyn had made a similar comment "jokingly" but his office did not want to comment.

Lansman now sits on the Labour Party ’s ruling body and his Momentum group has a membership of more than 40,000 - more than half the reported membership of the Conservative Party.

(Image: Rex Features)

In an interview with the left-wing columnist Owen Jones, Lansman explained that Momentum did not foresee a Corbyn leadership victory but instead wanted to shift the debate within the Labour Party to the left.

He said: “There was the idea that if we could open up the debate to alternatives and in particular to alternatives to austerity then we could keep alive that debate in the Labour Party thereafter and there fore have some influence on policy even if we couldn’t win the leadership.”

The veteran leftwing activist explained that there objectives changed as it became more evident that victory was possible.

(Image: PA)

Lansman, who is himself Jewish, said Labour has “failed to deal sufficiently deeply with antisemitism” and he said there was a problem that “people were in denial”.

“The problem is bigger than I used to think, I’ve seen it appear on my own Facebook .”

But he insisted the left and right wings of the party are committed to dealing with the issue.

“There is not one single person on that NEC who doesn’t want to deal thoroughly with the problem of antisemitism,” he said.

“And not only that, we are more united on antisemitism than we are on pretty much anything else in the party on wanting to eradicate it.”