Jeremy Corbyn will never be permitted to stand as a Labour MP at an election again, senior Labour figures have said. The former Labour leader was told last year he had to apologise for his claims that the extent of antisemitism in the party had been “dramatically overstated”. Keir Starmer has refused to restore the whip to his predecessor, effectively suspending him from the parliamentary party, unless he does so. However, the Guardian understands that even if Corbyn does apologise “unequivocally, unambiguously and without reservation” the leadership would be reluctant to let him return. One senior Labour figure said: “Jeremy Corbyn is never getting back in. He would be toxic to our chances of winning back some of the seats we need to win back.” It means that if Corbyn wants to remain an MP, he will have to stand as an independent in his Islington North seat. Allies of the former Labour leader have signalled he will run for the seat regardless of whether he gets the whip restored. One said locals in his north London seat respected him for his constituency work. Another ally said Corbyn seemed to be the only one not to have “fully realised” that he would not get the whip restored. Reflecting on Starmer’s recent purge of leftwing candidates from selection battles, an insider said Corbyn had no chance as Starmer was using the whip as “his personal plaything”. Corbyn won the seat with 63.4% of the vote in 2019, a thumping majority of 26,188. Sources close to Corbyn’s camp believe he has a strong support base. Labour party chiefs are said to be looking for a strong candidate in the constituency, which Corbyn has held since 1983. “The local party is likely to be difficult and the campaign will be very tough if Jeremy stands as an independent,” one source said. “But we think we’d win. We’d have plenty of volunteers and there would be no shortage of money for a campaign.” Should Corbyn decide to run at the next election as an independent, it would pose a potentially existential dilemma for Momentum, the grassroots leftwing group that emerged out of Corbyn’s leadership campaign, which has become a pressure group for the Labour left and the loudest critic of Starmer’s leadership. Senior Labour sources have made it clear that should Momentum campaign for Corbyn, it would be proscribed as an organisation by Labour – similar to the way Militant or other leftwing groups that challenged Labour MPs have been treated. Neal Lawson, the director of the cross-party campaign organisation Compass, has written to Labour’s general secretary, David Evans, criticising Labour’s “heavy-handed approach” to selections. “Dramatically narrowing the range of candidates eligible for selection on increasingly spurious grounds will not help Labour win office or transform the country,” he said. In the latest string of controversial election battles, Labour dissolved Kensington’s selection committee because of alleged leaks and because the regional party had to launch a “serious investigation” into antisemitism. The party selected three candidates: Mete Coban, Joe Powell and Afsana Lachaux, a former aide to Gordon Brown. The leftwing candidate Kasim Ali was blocked from the shortlist. A source criticised the move as “another blatant stitch-up” with the central party “disenfranchising the democratically constituted local body” to block leftwingers. The constituency’s former MP Emma Dent Coad was blocked from its long list. She claimed it was “plain as day” that the party was being “factionally abused” and was no longer “fit for purpose”. Lawson added: “In one case a former Tory MP who defected to Labour [Christian Wakeford] has been waved through the whole trigger process with no local democratic decision-making at all. The motive for this is … one side wants to gain all power and influence and stifle dissent.” Blasting the battle between factions of the Labour party, he said: “The zero-sum game between the right and left … is now reaching dangerous levels and a price will be paid by the country.” One insider stood by Labour’s decision to select Wakeford to run in Bury South claiming theMP had made a bold decision to cross the floor. Another said Wakeford would have wanted the opportunity to face local members.