Keir Starmer has been accused of a “grubby stitch up” over his plans to change the way Labour’s leader is elected.
Under the proposal, the one member, one vote (OMOV) system would be replaced with a return to the electoral college made up of the unions and affiliate organisations, MPs and party members.
Starmer has briefed the shadow cabinet on his plans and will set them out to trade union leaders on Wednesday ahead of the party’s conference which starts on Saturday.
“Our rules as they are right now focus us inwards to spend too much time talking to and about ourselves, and they weaken the link with our unions,” he said. “These are two things that have got to change if we are serious about winning the next election.”
But the move has triggered a furious backlash from the left of the party which believes the changes are designed to prevent a left-wing MP like Jeremy Corbyn ever being elected as leader again.
John McDonnell, the former shadow chancellor, said it was a “huge mistake”.
“Keir was only elected 18 months ago,” he told BBC Radio 4′s Today programme on Wednesday morning.
“He was elected on one member, one vote. He never mentioned any of these reforms in that election itself. He is opening himself up to challenges of dishonestly on this.
“If it comes to the point where our members can’t trust him, you know what the Tories are going to say, if your members can’t trust you, how can the electorate.”
McDonnell added: “Look at the contrast there is going to be in the media.
“Boris Johnson strutting the world stage doing deals with Biden and other world leaders, trying to prepare for COP26 and what do we have? The Labour leader in grubby stitch up deals.”
Corbyn has also hit out at the plan. “Removing the current system of electing Labour’s leader – again reducing the members’ vote to one third while increasing the vote of MPs to one third – would be deeply undemocratic,” he said.
“It’s time to stop attacking Labour members’ democratic rights – and take the fight to the Tories.”
Richard Burgon, secretary of the Socialist Campaign Group of Labour MPs, said a return to the electoral college system would “treat members with contempt and must be rejected as anti-democratic”.
Unite’s general secretary Sharon Graham has written to Labour MPs saying the proposal to ditch the OMOV system introduced in 2014 was “deeply disappointing”.
“Unite believes in democracy and this proposal to reduce the entire membership to one third of the vote, while inflating the vote of Labour MPs to one third, is unfair, undemocratic and a backwards step for our party,” she said.
The TSSA transport union is also opposed to the “gerrymandering” move.