Teribus and Keith can take comfort from the fact that Corbyn would have still won by a wide margin if the election had been confined to full members of the Labour Party, with no £3 supporter votes an no voting by members of affiliated unions.

JeffB, there are few points you might not have factored in. For instance it's odds on that Cameron's majority will have gone by 2020; the EU referendum will hurt the Tories more than Labour, and we haven't seen even the first of the 40 per cent cuts in public service spending we've been promised.

On top of all that, Labour's membership will now rocket yet further. I've just rejoined myself after a break of many years. It is a membership that will be out on the streets in 2020, campaigning with more enthusiasm than there has been for any party in memory. (Just compare how the accessions of some other party leaders were received - Cameron, Brown, Hague, Miliband, IDS....)

Having made a small fortune from backing Corbyn when he was 22/1, I think I can afford to risk a few shillings on Labour winning the next general election.