It was always about Brexit.
As much as Labour tried to change the narrative to austerity, what motivated the British public to give Upper Class Twit of the Year Boris Johnson and his fox hunting buddies a five year license to trample all over the British commons was Boris' clear stand in favor of Brexit.
Open diamonds are flipped seats, which shows that nearly all of the flips from Labour to the Tories happened in majority Leave districts.
Corbyn's straddling the center on Brexit was his undoing. If he had stayed true to his Eurosceptic roots, we might be looking at a very different outcome.
Instead, Corbyn tried to court Remainer defectors (who ended up defecting anyway) with a second referendum, which drove rural and working class voters in the North and Midlands straight into the jaws of the Tories.
To make matters worse, Corbyn tried to distract from his mistake by changing the subject to Progressive issues, which now gives establishment types on both sides of the pond the perfect if phony excuse to bash them as unpopular.
I like Jeremy Corbyn and certainly was hoping he would win, but there's no denying Labour made a fatal error by leaving the door open to Remaining.
Bottom Line: The UK just had its second Brexit referendum yesterday. There won't be a third.