The prospect of an anti-Corbyn split in the Labour Party mounted last night after moderate MPs admitted plotting to form a 'breakaway' faction at Westminster.
Members of the 37-strong Co-Operative Party, who jointly sit as Labour MPs, privately drew up plans to win the right to sponsor their own Commons debates separately from Labour.
The Mail on Sunday understands they secretly consulted Commons clerks to see if Speaker John Bercow would grant them a new special status at Westminster.
The move was quietly shelved after the group – which includes arch-Corbyn critics such as Chris Leslie as well as Jewish MP Luciana Berger, who has slammed Mr Corbyn for inaction over anti-Semitism – were told they would have to form a whole new party to qualify for the new position.
But last night, allies of Jeremy Corbyn branded the abortive move a 'dry run' for a fully-fledged breakaway party.
One ally of the Labour leader said: 'This was clearly a bid to test the water for that rebel party and it's completely outrageous. These Labour/Co-Op MPs take the Party Whip so whoever was responsible should be disciplined.'
Co-Op party members hit back last night, claiming only someone with 'Corbynista paranoia' could see a threat to the Labour leader from the suggested manoeuvres.
They also pointed out that their members include some leading pro-Corbyn MPs such as Shadow Cabinet member Kate Osamor.
But the move emerged amid growing speculation at Westminster that plans for a new centrist party are being secretly prepared – despite Tony Blair warning yesterday that 'such an endeavour may be impossible'.
One senior Labour MP said the new party wanted to hit the ground running by immediately replacing the 35-strong Scottish Nationalists as the second Opposition party behind Labour in the Commons – giving it a leading role in Prime Minister's Questions each week. He said: 'There are various crucial hurdles the rebels have to meet but the first is making sure they launch with more than 35 MPs signed up.
'That would automatically put them ahead of the SNP and require the Speaker to recognise them as second Opposition party with the right to put two questions to the PM each week. That'd be immediately after Corbyn, who fails to skewer Theresa May at PMQs every week, and would let them show how much better the new party leader is.'
In an alliance dating back over 90 years, all the Co-Operative Party MPs sit with Labour and a distinction between the two parties is rarely drawn.
But earlier in the summer, Co-Op MPs privately raised fears they would not be given the chance to debate Mr Corbyn's plans to renationalise railways.
Last night, leading Co-Op MPs denied they had been making a first move to split the Labour Party, and insisted that neither Mr Leslie nor Ms Berger had been aware of plans to seek special status.
Gareth Thomas, chairman of the Co-Op Party at Westminster, said: 'We have discussions about how to operate in Parliament all the time so I struggle to see how anyone could present this as an anti-Corbyn thing. We are proud of our shared history with the Labour Party. We look forward to continuing our joint campaign to win the next Election together.'