What is really going on in politics? Get our daily email briefing straight to your inbox Sign up Thank you for subscribing We have more newsletters Show me See our privacy notice Invalid Email

Jeremy Corbyn has opened up an astonishing 20-point lead over his rivals in the race for the Labour leadership.

Private polling seen by the Daily Mirror shows Mr Corbyn set to top the ballot with 42%, way ahead of Yvette Cooper on 22.6%, Andy Burnham on 20% and Liz Kendall on 14%.

But once second preferences have been taken into account the veteran leftwinger is ahead by just two points on 51% to Ms Cooper’s 49%.

Some Labour MPs are now urging supporters of Mr Burnham and Ms Kendall to either back Ms Cooper or at least ensure she gets their second preference votes as the only way of stopping the Corbyn bandwagon.

Ballot papers for the contest are sent out on August 14, with the result announced on September 12.

Jeremy Corbyn storms ahead in private Labour poll Source: Private poll shown to the Daily Mirror

Harriet Harman denied the Labour leadership race has been infiltrated by left-wing extremists and Tory activists.

The acting leader said “rigorous due diligence” was being undertaken by party staff to root out infiltrators.

It follows fears that hard-left groups were signing up for £3 to vote for Mr Corbyn.

Some Tories are also alleged to have joined to vote for the left-winger believing it would be a disaster for Labour.

The growing buzz around Mr Corbyn, 66, has now seen him emerge as an unlikely sex symbol.

Women on the Mumsnet website revealed they find him “very sexy” and “attractive in a world-weary old sea dog sort of way”.

(Image: PAUL ELLIS/AFP/Getty Images)

Asked about the findings on BBC’s Women’s Hour, the Islington MP replied: “This is the most embarrassing thing I’ve ever heard.”

He added: “I had a bit of a chuckle about it, but I’m actually a bit embarrassed, to be quite honest.”

Mr Corbyn, who launched his women’s manifesto, also rejected claims he was “destroying” Labour’s chances of winning the next election.

“No, I’m not convinced about that at all.

"What’s interesting to me is in our campaign lots of young people are getting involved, often for the first time in politics, because they do think there needs to be a challenge to the cross-party agreement that was around on variations of austerity around at the General Election, and young people are excited about this,” he said.

A spokeswoman for the Burnham campaign said the results did not match its data from polls and phone banks.

“There’s only person who can stay true to Labour values and win the election and people recognise that’s Andy Burnham,” she said.

Video Loading Video Unavailable Click to play Tap to play The video will start in 8 Cancel Play now

An ORB for the Independent found 76% of people thought the party was now less electable than it was at May’s general election, with only 24% saying it was more electable.

Meanwhile, comedian Greg Davies said he wanted his ex Liz Kendall to win.

The couple split amicably a few months’ ago and have remained friends.

Mr Davies said he “absolutely” hoped she would win.

“She would be an amazing leader. It was no surprise to me at all that she ran and it’s no surprise to me at all that people are taking her seriously - they should,” he told The Times.