John McDonnell faces a Labour revolt to unseat him as shadow chancellor after he said there was “a lot to learn” from Karl Marx's Das Kapital.

Shadow cabinet sources said Jeremy Corbyn’s right-hand man, who has described himself in the past as an “unapologetic Marxist”, had done nothing to help Labour’s cause with a month to go to the general election.

And while they said it was too late to mount a challenge to Mr McDonnell or Mr Corbyn before the June 8 ballot, there will be “no holding back” when Labour MPs come back to Parliament after the election.