It is understood that Azhar Ali has also been suspended from the party pending an investigation.

A Labour Party spokesperson said: "Following new information about further comments made by Azhar Ali coming to light today, the Labour Party has withdrawn its support for Azhar Ali as our candidate in the Rochdale by-election.

"Keir Starmer has changed Labour so that it is unrecognisible from the party of 2019.

"We understand that these are highly unusual circumstances but it is vital that any candidate put forward by Labour fully represents its aims and values.

"Given that nominations have now closed Azhar Ali cannot be replaced as the candidate."

Politics latest: Labour withdraws support for Rochdale candidate

Mr Ali's candidacy had been thrown in the spotlight after the Mail on Sunday reported he had told a meeting of the Lancashire Labour Party that Israel deliberately allowed the Hamas atrocity to take place in order to give it the "green light" to invade Gaza.

Mr Ali had earlier issued an "unreserved" apology for the "deeply offensive, ignorant and false" comments.

Speaking to reporters after the decision to withdraw support was made, Labour's national campaign co-ordinator, Pat McFadden, said Sir Keir Starmer had taken the "tough but necessary" decision.

"When Keir Starmer became leader of the Labour Party, he said he would change the Labour Party and expect that every candidate and MP would operate to the highest standards," he said.

"And although it is a difficult decision, today, he's put those words into action. And unfortunately we've had to take this difficult decision."

Asked what had changed in the last 24 hours since he himself defended Labour continuing to support Mr Ali, the senior MP said: "More comments have come to light which meant we had to look at this situation again.

"Once we saw those comments, Keir Starmer took [the] swift decision, took the tough but necessary action to withdraw support for Mr Ali's candidacy."

However, Mr McFadden would not say what this "new information" was, adding: "This was a difficult decision, but it's the right thing to do."

Mr McFadden also rejected suggestions Labour had let the Jewish community down, saying Sir Keir's decision was testimony to his pledge to "root antisemitism out of the Labour Party".

"Tonight the decision he has taken is evidence that he is sticking by that, no matter what the circumstances," he added.

Today Sky News reported that Labour had received an official complaint from the campaign group Labour Against Antisemitism (LAAS), which branded the remarks "antisemitic".

LAAS, a campaign group founded by Labour members to combat antisemitism within the party, earlier today called for Mr Ali's immediate suspension as a candidate and party member.

Alex Hearn, who is a director of the campaign group and member of the Labour Party, submitted a formal complaint against Mr Ali this afternoon in which he wrote: "The accusation that Jews plotted a massacre of innocent people for their own bloodthirsty gain is antisemitic."

Although Labour has withdrawn its support for Mr Ali, it is understood he will still appear on the ballot paper in the by-election as the party's candidate.

Prime Minister Rishi Sunak immediately seized on the developments in Rochdale to further his accusation that Sir Keir had "no principles at all".

"Keir Starmer has been running around for the last year trying to tell everybody 'OK, Labour Party's changed'," he said.

Read more:
Israel should 'stop and think' on Rafah offensive, says David Cameron, as UK sanctions West Bank settlers
Labour candidate 'fell for online conspiracy theory' about Hamas attacks, shadow minister says

"Well, look what just happened in Rochdale, a candidate saying the most vile conspiracy theories, antisemitic, and what happened?

"He's stood by and sent cabinet ministers to support him, until literally five minutes before I walked on tonight, under enormous media pressure, has decided to change his mind on principle. No principles at all.

"So no the Labour Party hasn't changed. It's a con."

And Grant Shapps, the Conservative defence secretary who is Jewish, questioned why Labour had not acted sooner, writing on X: "A real shame that communities have had to once again endure prolonged Labour support for someone spewing antisemitism and conspiracy theories.

"This should have been dealt with immediately."

The Jewish Labour Movement statement said the party was "right to cease campaigning" for Mr Ali.

"As he cannot be removed from the ballot, we believe it is correct that he will not sit as a Labour MP if elected."

See below the full list of candidates and the political parties they represent:

Azhar Ali, (listed as Labour Party, but now removed as their candidate)
Mark Coleman, Independent
Simon Danczuk, Reform UK
Iain Donaldson, Liberal Democrats
Paul Ellison, The Conservative Party Candidate
George Galloway, Workers' Party of Britain
Michael Howarth, Independent
William Howarth, Independent
Guy Otten, Green Party
Ravin Subortna, The Official Monster Raving Loony Party
David Tully, Independent