Either YouGov is completely wrong (again), or Jeremy Corbyn has at least a 50/50 chance of becoming Labour leader

I was extremely sceptical about the reports a few days ago that "private polls" were supposedly showing Jeremy Corbyn in the lead, because it seemed to me that one or more of his opponents might have been leaking half-true information to suit their own agendas.  However, it's much harder to maintain that scepticism now that we have detailed numbers from a public poll telling much the same tale.  Bucket-loads of caution still need to be applied, because internal party elections are notoriously hard to poll accurately, and it could be that the greater enthusiasm of Corbyn's supporters is skewing the results.  But there's no getting away from it - unless YouGov are way out, Corbyn is clearly in with a genuine shout, and that's an extraordinary enough story to be getting on with.

YouGov poll of Labour members and supporters (17th-21st July)

First preferences :

Jeremy Corbyn 43%
Andy Burnham 26%
Yvette Cooper 20%
Liz Kendall 11%

Final run-off :

Jeremy Corbyn 53%
Andy Burnham 47%

I'm going to be very interested to learn more about the methodology used for this poll.  The most obvious question is whether YouGov have been able to interview people who definitely have a vote in the leadership election, or whether the sample is compromised by the inclusion of people who are Labour "supporters", but not registered supporters who have actually paid the token £3 fee.

I'll also be looking to see whether YouGov asked every respondent for an exhaustive list of preferences, or whether they just tested each hypothetical run-off result.  The latter approach would be much less robust than the former.  There was speculation on LabourList the other day that Liz Kendall's second preferences were breaking decisively for Yvette Cooper, and if there's any truth in that, you'd think it might be quite close between Cooper and Burnham for the second place in the run-off, in spite of Burnham's 6% advantage on first preferences.  LabourList also suggested that the second preferences of Burnham supporters seemed to be fairly evenly split between Cooper and Corbyn, whereas Cooper's supporters were breaking heavily for Burnham.  If that's right, Corbyn should be praying that his final opponent is Cooper, because otherwise he won't be getting any of the transfers from Burnham.

Long-term readers of this blog might recall that I was bemused by an article that billed the 2012 Greek general election as "the most important election ever".  I thought that was pushing it slightly, given that an election in Germany in the 1930s led directly to the most catastrophic conflict in human history, and to the extermination of six million Jews.  The Labour leadership election isn't the most important election in history either, but if the result is as finely-balanced as YouGov are suggesting, we're faced with the startling prospect of a relatively small number of voters holding the political destiny of the UK in their hands over the coming weeks.  There are no nuanced outcomes in a leadership race - it's winner-takes-all, and the difference between a Burnham win and a Corbyn win is unimaginably huge.

What we don't know, however, is in exactly what way Labour members and supporters may be shaping our destiny, because the consequences of Corbyn emerging as leader are so hard to predict.  Is there any chance at all that the various factions of the party could hold their noses and unite behind him, perhaps at the cost of a Frankenstein "Dream Team" Shadow Cabinet featuring Blairites in senior positions?  That seems unlikely to me, but if it did happen it could be the nightmare outcome for the SNP, because a viable Corbyn leadership might just get Labour back into the game in Scotland.  More plausibly, will Corbyn be deposed?  If so, will the leadership election be re-run with a broader range of candidates, perhaps including someone who - unlike Andy Burnham - actually looks like a potential alternative Prime Minister?  Or will Corbyn stay in harness, but suffer an SDP-style breakaway?  Would it be a big or a small breakaway?  Might the new party follow the precedent set by the SDP and go into alliance with the Lib Dems?  Would that be an unequal marriage?  Could Tim Farron find himself swallowed up before he even has a chance to get comfy in his chair?

So many questions, and almost no answers at this stage - other than to say that if Corbyn wins, all bets are well and truly off.

Final thought : There are a number of right-wing journalists who seem to think that the Labour rank-and-file has taken leave of its senses, and that a Corbyn victory would be the most insane outcome to a leadership election in modern British history.  Can I just gently remind them that in 2001, Iain Duncan Smith defeated Ken Clarke for the leadership of the Conservative party.  I'll just say that again to let it sink in - IAIN DUNCAN SMITH defeated KEN CLARKE.  Until someone invents a time machine and erases that mind-boggling event from history, I think we can safely say that Jeremy Corbyn defeating the dismal Andy Burnham would not be the most irrational result in recent times.