The shadow leader is facing a backlash from the left-wing of his party and some Conservatives after standing by Azhar Ali, who suggested Israel had allowed the 7 October Hamas attack to take place in order to invade Gaza.
The row intensified as Sir Keir was urged to re-admit other MPs suspended in antisemitism rows, with some questioning the alleged difference in his approach to left-wing MPs and those seen as Starmer loyalists.
Labour peer Prem Sikka told The Independent that Sir Keir’s backing for Mr Ali shows that there is “one set of rules for anybody on the left, and another for favourites of the Labour leader”.
Tory MPs also rounded on Sir Keir, saying his backing for Mr Ali showed Labour “has not changed” since Jeremy Corbyn’s leadership, when the party was dogged by its handling of antisemitism complaints.
Labour, meanwhile, publicly stood by their candidate, with shadow minister Nick Thomas-Symonds insisting it would be “unfair” to conclude there is a problem with Labour in Rochdale, adding that Mr Ali had simply “fallen for an online conspiracy theory”.
He also claimed there had been “a transformation” in the Labour Party’s handling of antisemitism under Sir Keir, arguing that the cases of suspended MPs were different. “In this case... there’s been the apology, the retraction, but also that recognition of the level of offence that has been caused and then a commitment to seeking to rebuild trust,” he told Times Radio when asked about the difference.
Mr Ali cannot now withdraw from the 29 February by-election, where he was picked as Labour’s candidate to replace the late Sir Tony Lloyd.
Labour figures have urged the party to let him fight the contest to stop George Galloway – who is campaigning against Labour’s stance on Gaza – from winning the seat.
One shadow minister told The Independent Sir Keir needed to be clear that Mr Ali, if elected, “will not be a Labour MP… and that we will replace him with an appropriate candidate for the general election”.
“It is a mess… and a completely avoidable one,” they said.
Former justice secretary Sir Robert Buckland told The Independent: “Once again, Labour is showing that they have not changed, are not to be trusted and are nowhere near ready for government.”
Kate Osamor was suspended last month over a Holocaust Memorial Day post suggesting the Israeli action in Gaza is genocide. Diane Abbott was suspended after writing a letter suggesting Jewish people are not subjected to the same racism as some other minorities.
And Andy McDonald was suspended for using the controversial phrase “between the river and the sea” in a pro-Palestine rally speech. All three are on the left of the Labour party and supported former leader Mr Corbyn.
Corbyn-backing campaign group Momentum slammed what it called an “authoritarian, factional purge of the Left from Keir Starmer”. It added that Mr Ali’s case showed the other suspensions were “not about anti-racism”.
Lord Sikka also called on Sir Keir to restore the whip to those left-wing MPs, all of whom were suspended over what he said were much less serious incidents. “I just can’t understand it,” he said.
The former London minister Paul Scully said the party was “the same as ever underneath”, echoing left-wing MPs and activists who believe Sir Keir’s decision to stick by Mr Ali is driven by “political expediency”.
He said: “How can Keir Starmer stick with someone peddling the most heinous and offensive accusations about Israel? Because politically it’s the easiest short-term solution but storing up a whole load of trouble ahead.”
Pointing to the case of Ms Osamor, he said: “I’m sure Kate Osamor who lost the whip for less is scratching her head at this latest act of political expediency.”
Another Labour MP told The Independent: “Rochdale is a mess. I think they know that if they lost the candidate, that might just galvanise support for alternative independent candidates.”
Labour on Sunday issued a statement on behalf of the candidate after the Mail on Sunday published comments from a recording of him telling the Lancashire Labour Party that Israel had been warned of the attack before it happened, but they “deliberately took the security off”.
Mr Ali is alleged to have said: “The Egyptians are saying that they warned Israel 10 days earlier... Americans warned them a day before [that] there’s something happening... They deliberately took the security off, they allowed... that massacre that gives them the green light to do whatever they bloody want.”
The Labour councillor is also alleged to have said that Sir Keir has “lost the confidence of the parliamentary party”. He said: “A lot of the MPs I’ve spoken to, non-Muslim MPs, feel that on this issue, he’s lost the confidence of the parliamentary party.”
In the statement issued on Sunday morning, Mr Ali said: “I apologise unreservedly to the Jewish community for my comments which were deeply offensive, ignorant, and false.
“Hamas’ horrific terror attack was the responsibility of Hamas alone, and they are still holding hostages who must be released. October 7th was the greatest loss of Jewish life in a single day since the Holocaust, and Jews in the UK and across the world are living in fear of rising antisemitism. I will urgently apologise to Jewish leaders for my inexcusable comments.”
Joe Glasman, head of political and government investigations at Campaign Against Antisemitism, said: “This man does not belong in a major political party, let alone in parliament, yet Labour is, incredibly, still backing his candidacy after a quick apology.
“This is distressingly familiar to days that Sir Keir Starmer promised were behind us. This is not tearing antisemitism out ‘by its roots’.”
Mike Katz, the national chairman of the Jewish Labour Movement, said his group would not campaign in Rochdale as Mr Ali had “destroyed his past record of allyship with the Jewish community” with his “totally reprehensible” comments.
But he stopped short of calling on Labour to drop the candidate, warning that the “alternative in Rochdale is George Galloway” whose victory would “harm the Jewish community far more than electing Ali”.
He added: “We know how far the party has come under Keir Starmer in tackling antisemitism and that the party, from Starmer down, is as shocked and disgusted by Ali’s comments as we are.”
Adam Langleben, director of the Progressive Britain think tank, said Mr Galloway was “a greater evil” and that Ali should win. But he added: “Maybe he loses the whip once he has done it. Probably he isn’t allowed to contest the general election.”
The row also threatened to once again highlight divisions within Labour over its stance on the Gaza conflict, with Sir Keir’s initial refusal to call for an immediate ceasefire facing serious criticism from within the party ranks.
About 20 per cent of the electorate and 30 cent of the population in Rochdale are Asian, with polls nationally suggesting Labour’s vote could be hit by Asian people unhappy with the party over Palestine and its perceived support for Israel.