I think Labour's one chance of winning a snap election, albeit a very slim one, was for it to consolidate behind Corbyn, and help him to capitalize on the 'brexit buyers' remorse', which financial markets are turning into a roaring conflagration as we speak.
If they're going into a bitter and divisive leadership campaign, which Corbyn is almost bound to win if his name is on the ballot (according to party rules, it must be), then they might as well throw in the towel now, and prepare for a Boris coronation.
EDITED: 27 Jun 2016 12:36 by DSMITHHFX