Jeremy Corbyn's harshest critics from within his own party benefited from the "Corbyn surge" last night as Labour made significant gains.

Some of those who asked Mr Corbyn to resign - and even Owen Smith, who contested him as leader - have apologised, conceding that they were wrong.

Owen Smith said: "I was clearly wrong in feeling that Jeremy wouldn’t be able to do this well. And I think he’s proved me wrong and lots of people wrong and I take my hat off [to him]...

“I don’t know what Jeremy’s got but if we could bottle it and drink it we’d all be doing very well.”

Angela Eagle, who at one point was touted as the Labour establishment’s likeliest challenger to Mr Corbyn, said his campaign praised his leadership, saying it had “resonated with the electorate”.

Lord Mandelson, seen by many as the architect of the Blairite revolution which steered the party to the centre and three election victories, said Mr Corbyn’s campaign “very sure-footed”.