Rarely a week passes without reports that Labour rebels are planning a split of some kind. The latest story, in the Daily Telegraph, suggested that rather than creating a new party (an option that has never been on the cards), MPs intend to form an alternative parliamentary grouping. This would involve electing their own leader and seeking designation as the official opposition.

The idea has been discussed in Labour circles ever since Joe Haines, Harold Wilson’s former press secretary, called in January in the New Statesman for the parliamentary party to unilaterally declare independence. But it is not a course that MPs intend to pursue, even if, as most expect, Jeremy Corbyn is re-elected.

Labour backbenchers Toby Perkins and Wes Streeting told the NS they knew of "no one" who was advocating the idea, while Jamie Reed said he thought the story was a "put-up job". He added: "McDonnell and Corbyn have no regard for the party. Never have had, never will. They are ones angling for a split. The 81 per cent of Labour MPs who know what we need to do to have a chance of winning in 2020 have no intention of going anywhere." Three senior rebels described reports of a split as “bollocks”. Another said: "Nobody can track down likely source of the Telegraph piece, so it may just be a lone voice. I don’t think it’s a runner."

MPs said that further leadership challenges were likely before anyone gave serious consideration to a split. But one added: "If, however, the hard left pursued deselections then those ejected from their own party would most likely feel compelled into a separate party option, which really would be a disastrous split. Unless that’s what McDonnell meant by ‘so be it’." The shadow chancellor is alleged by leadership candidate Owen Smith to have "shrugged his shoulders and said 'If that’s what it takes'" when privately challenged on whether he was prepared to split Labour (a claim described by McDonnell as "complete rubbish").

Corbyn’s opponents believe that some MPs will follow shadow Home Office minister Sarah Champion and return to the frontbench if he wins the contest. But most of the 172 who backed the no confidence motion have no intention of doing so. “We’ve crossed the Rubicon, there’s no going back,” said Streeting. “This is irreparable while Jeremy remains leader.”

The SNP is currently bidding to be made the official opposition on the grounds that Corbyn has the support of just 40 MPs, while it has 54. But the rebels believe the Speaker will not award the nationalists this designation since they, unlike Labour, do not even have the potential to form a full frontbench team. Catherine Haddon of the Institute for Government told the NS: "The only argument here would be if the 81 per cent of MPs who voted against Corbyn seemed likely to refuse the whip or to refuse to serve in a Corbyn government were one likely. If that happened the argument does change. But we are not there yet."

Both Corbyn supporters and their opponents have sought parliamentary advice on which side would have the right to use the Labour name in the event of a breakaway. The expectation, based on the Registration of Politicial Parties Act, is that the leader would retain ownership.

MPs acknowledge the possibility of a future split, but the option is not being pursued at any significant level. Though most rebels expect Corbyn to be re-elected, they hope to narrow his margin of victory and to win among full party members. This, they say, would deny the leader the right to boast of an "overwhelming" mandate. But without a dramatic change in Labour's selectorate, many now believe that it is only through a general election that the party's internal struggle will be resolved.