Alastair Campbell warns Labour against electing Jeremy Corbyn

Alastair Campbell has warned Labour risks "driving itself off a cliff" with Jeremy Corbyn as leader, as a new poll put the left wing MP ahead.

Labour's former communications director is urging support for "anyone but Jeremy Corbyn" in the leadership vote.

The YouGov poll for The Times of 1,400 eligible voters put Mr Corbyn on 53%, 32 points ahead of Andy Burnham.

The Islington North MP urged caution and the poll was dismissed by rival candidate Yvette Cooper's campaign.

BBC political correspondent Robin Brant said while the poll results were "startling" they would be treated with a "healthy dose of scepticism" given pollsters' failure to predict the general election outcome.

'Democratic process'

Mr Corbyn told BBC Radio London his campaign was going "very well" but added: "We should be a little bit cautious."

There is still time for people to register as supporters and no ballot papers have been sent out yet, he added.

Asked about Mr Campbell's criticism, he said the leadership contest was "very democratic".

He said the large number of new Labour Party members was a "good thing", adding: "If they choose somebody, the leader that others don't like, well I think we have to accept the democratic process."

Mr Campbell, who was head of press during former PM Tony Blair's government, said he had vowed not to get involved in the leadership debate but now felt he needed to warn people of the "car crash" which "appears to be happening to Labour right now".

Writing in his blog he said: "Whilst I accept that I cannot survey the post-electoral scene and say with any certainty that a Labour party led by Andy Burnham, Yvette Cooper or Liz Kendall will win the next election, I think I can say with absolute certainty that a Corbyn-Tom Watson led Labour party will not.

"For that reason alone, I agree with Alan Johnson that what he called the madness of flirting with the idea of Corbyn as leader has to stop.

"That means no first preferences, no second preferences, no any preferences. It frankly means ABC: Anyone But Corbyn."

Mr Campbell said although he thought Mr Corbyn was "an OK guy, a good MP, and his stance clearly chimes with many people's views of anti-austerity", his ability to lead and hold the party together "is likely to be low".

He added: "Once the pressures of real, difficult decisions and the day to day leadership of the main opposition kick in, I fear that activists currently cashing in on perceived 'betrayal' by past Labour leaders are going to end up feeling very badly let down."

Mr Campbell was criticised by Labour MP Diane Abbott, with the two clashing on Twitter about Labour's record.

If the findings in The Times poll were repeated in the leadership election, Mr Corbyn would win without the need for second preferences to be counted.

YouGov president Peter Kellner said he "would personally be astonished if Corbyn does not end up as Labour's leader" despite voting not starting until Friday and the result not being declared until 12 September.

The poll was dismissed by Ms Cooper's campaign.

Its spokeswoman said: "This does not reflect our extensive phone banking data, which does not suggest any single candidate will receive 50% of first preferences."

On Monday Barry Sheerman became the latest Labour MP to call for the leadership contest to be "paused" over fears it had been infiltrated by supporters of other parties.

These fears have been rejected by Labour, which says robust checks are in place.

Labour leadership contest

Labour leadership candidates (l-r): Liz Kendall, Andy Burnham, Yvette Cooper, Jeremy Corbyn

• Who are the candidates? Andy Burnham, Yvette Cooper, Jeremy Corbyn, Liz Kendall

• Dates: Ballot papers will be sent out on 14 August; voting can take place by post or online. They must be returned by 10 September. The result is announced on 12 September

• Who can vote? All party members, registered supporters and affiliated supporters - including those joining via a union

• What is the voting system? The Alternative Vote system is being used so voters are asked to rank candidates in order of preference

• How does it work? If no candidate gets 50% of all votes cast, the candidate in fourth place is eliminated. Their second preference votes are then redistributed among the remaining three. If there is still no winner, the third place candidate is eliminated with their second preferences (or third in the case of votes transferred from the fourth place candidates) redistributed. It is then a head-to-head between the last two candidates

At-a-glance profiles of the four contenders