Sharon Graham, general secretary of Unite, stated Mr Corbyn – currently suspended – “is a Labour MP” and appeared criticised the party’s internal investigation into the former leader.
“Jeremy Corbyn is a Labour MP. The party has gone through an investigation, in inverted commas,” she told BBC’s Sunday with Laura Kuenssberg, using air quotes when she said “investigation”.
She added: “It’s clear he’s a Labour MP. And, of course, I think if he stood in his constituency, he’d win, actually, I think he probably would win in relation to that. So rather than creating barriers, why don’t we try and bring people together?”
Shortly after becoming Labour leader, Sir Keir Starmer removed the party whip from Mr Corbyn – meaning he cannot sit and vote with the party – after he claimed allegations about anti-Jewish racism had been “dramatically overstated” by political opponents.
The comments followed the Equality and Human Rights Commission [EHRC]’s report into antisemitism in the Labour party, which concluded unlawful acts of harassment and discrimination took place while Mr Corbyn was leader.
Sir Keir has previously suggested that Mr Corbyn may be allowed to return to sitting as a Labour MP if he apologises for the comments. However, more recently, he has said Mr Corbyn will not have the Labour whip restored while he continues to associate with the campaign group Stop the War coalition.
Sir Keir said it was “very clear” those who wanted to be Labour MPs had to be supporters of Nato and reject “false equivalence” between Nato and Russian aggression.
It comes as Unite members join the Royal College of Nursing (RCN) members in staging what is expected to be the biggest day of industrial action in the history of the NHS.
Commenting on the strikes, Ms Graham claimed the government has refused to enter into talks over pay to avert the strikes and called on Labour to say it would make different choices from the government.
Ms Graham said: “I can tell you categorically that there have been no conversations on pay whatsoever with Rishi Sunak or [health secretary] Stephen Barclay about this dispute in any way, shape or form.”
“I do think that Labour needs to come out and say that they would make different choices. You don’t make choices on these profiteering companies. We cannot put this country through austerity mark two again.”
Business secretary Grant Shapps has said he is concerned that the planned strike by ambulance staff on Monday will put lives at risk.
Mr Shapps said the RCN had “very responsibly” told the NHS about where they will be striking and therefore enabled emergency cover to be put in place – but claimed Unite, Unison and GMB unions representing ambulance workers have not provided such information.
Ms Graham accused Mr Shapps of lying about ambulance workers providing minimum cover during industrial action. “I haven’t used this word so much about politicians, I don’t think ever in 30 years, but he’s actually lying.
She added: “The idea that he is saying that ambulance workers did not do minimum cover in the dispute is an absolute utter lie. And it’s important that we rectify that this morning. That is not true.”
In a letter to the PM, RCN general secretary Pat Cullen said a “meaningful” pay offer from the Sunak government could still avert strike action.
She drew a comparison with his swift action to sack Conservative chairman Nadhim Zahawi after he was found to have breached the ministerial code in relation to his tax affairs.
Labour declined to comment on Ms Graham’s remarks.