I’m not sure really how many Labor voters would support Corbyn. Sure, they like to say that they are Labor, but do they really want him in to wreck take their country even further off track? I don’t think so.
This got brought up after BREXIT. Labour has two wings to it...the youth side which is like a Bernie Sanders machine, and the union-worker type which feels that Corbyn is a ‘joke’. Part of the mild success of UKIP was drawing small numbers of the union-worker crowd over.
If you had some rushed-up election...Corbyn isn’t really a dramatic element, and he’s mostly pro-BREXIT (he just doesn’t say it much).
That’s why I think this would be a fairly unusual election if May has to call for it. UKIP could make this about Tommy Robinson and BREXIT.