Guessing games about what will happen in an election five years down the road are a bit pointless. Opinion polls, for what they are worth don't give Labour much chance, whoever is leader, but than they aren't really measuring anything real. In fact even on those Corbyn scores better than the others - only 21% predict him winning in 2020, but that's better than the predictions for the others, with 19% for Burnham, 15% for Cooper and 11% for KendLl.

And the truth is, nobody knows. When the Tories picked Margaret Thatcher as leader that was generally seen as disastrous for them.