Keir Starmer has said he can't see the circumstances where Jeremy Corbyn could stand as a Labour candidate at the next election.
The Labour leader suggested there was no way back for his predecessor, who lost the whip in 2020 following his response to a damning report by the equalities watchdog into anti-Semitism in the party.
Mr Corbyn initially said that the scale of anti-Jewish sentiment in Labour's ranks under his leadership had been "dramatically overstated for political reasons" and offered no apology following the Equality and Human Rights Commission's findings.
He later said concerns about anti-Semitism were "neither 'exaggerated' nor 'overstated'" - but his initial statement remains on his official Facebook page.
Mr Corbyn had his Labour party membership reinstated within weeks but the he has not regained the whip, which means he cannot sit as Labour MP in Parliament.
"I don't see the circumstance in which that can happen," Mr Starmer told the Today programme.
"Obviously we haven't got to the selection of that constituency yet but I don't see the circumstances where Jeremy Corbyn will stand as a Labour candidate."
Labour have been prioritising choosing candidates in the most marginal seats for the next election, which is expected in 2024.
Mr Corbyn, who has represented Islington North since 1983, won a 26,188 vote majority in 2019. He could stand in the seat as an independent, relying on this popularity locally and his supporters base.
Asked if Mr Corbyn could stand against Labour as an independent, Mr Starmer said: "I can only speak for Labour Party, I can't speak for Jeremy on this."
Senior Labour figures expect the issue will need to be confronted soon, as party chiefs have to select a candidate for Mr Corbyn's seat.
Mr Corbyn was told he had to apologise for his comments following the EHRC probe if he wanted to get the whip back - but he has failed to do so.
Momentum, the grassroots activists network which supported his leadership, tweeted in response to Mr Starmer: "The circumstances would be that you follow the Party's rules and allow a Labour member and sitting MP to restand, not abuse the whip for factional gain."
Mr Corbyn told the Mirror: "I am honoured to be the full-time representative of Islington North, and will continue to tackle the most important issues - the cost-of living crisis, stagnant wages and growing inequality - affecting my constituents.
"I was elected as a Labour MP and proud to be so. I have made it clear that the whip was wrongly removed, and it should be re-instated.
"Labour members have the democratic right to choose their candidate. Currently, members in Islington North are being denied that right, and it should be restored immediately."
Meanwhile, Mr Starmer poked the Brexit hornets nest by saying said he does not believe returning to the single market would boost the UK's economic growth.
The Labour leader said he does think there is a case for a "better Brexit".
Asked if being part of the single market would boost economic growth, he said: "No, at this stage, I don't think it would. And there's no case for going back to the EU or going back into the single market."
He argued trade has "gone down" because "the deal that we've got is not a very good deal".
Mr Starmer added: "Do I think, just to take your question head on, that going back into years of wrangling, years of uncertainty, is going to help our economy? No, I don't."
