Allies of former Labour leader Jeremy Corbyn have called for him to be reinstated as one of the party’s MPs, arguing he is being “persecuted” by successor Sir Keir Starmer.
Unite union leader Len McCluskey described Sir Keir’s decision not to bring back Mr Corbyn as “vengeful”.
And former Labour chairman Ian Lavery called it “undemocratic”.
But Sir Keir said Mr Corbyn’s remarks on the scale of anti-Semitism within Labour had “undermined” trust.
He added: “It is the task of my leadership to fix what I have inherited. That is what I am resolute in doing.”
Mr Corbyn was suspended from Labour at the end of October after a damning report by the Equality and Human Rights Commission (EHRC) on the party’s response to allegations of anti-Semitism during his tenure as leader.
The move followed him saying opponents had “dramatically overstated” the scale of the problem within Labour for political gain.
The party’s ruling body decided on Tuesday to readmit Mr Corbyn as a member.
But this did not mean he would automatically be reinstated as a Labour MP, and on Wednesday Sir Keir decided not to restore the party whip to his predecessor – meaning he will continue to sit in the House of Commons as an independent.
Sir Keir promised to keep the situation under review.
There is no doubt Jeremy Corbyn’s supporters will keep objecting loudly to what has happened, and that could get extremely bumpy.
But cracking down on anti-Semitism is meant to be at the top of Sir Keir Starmer’s to-do list.
If he wanted to keep the promise he made solemnly to the Jewish community, did he really have any choice?
Board of Deputies of British Jews president Marie van der Zyl said Sir Keir had “taken the appropriate leadership decision”, adding Mr Corbyn had been “shameless and remorseless for what he has put the Jewish community through”.
Shadow justice minister Peter Kyle tweeted in support of Sir Keir, saying: “We knew there would be moments that challenge and test us. The last 24 hours were unnecessarily difficult but Keir Starmer has acted authoritatively. We are moving forward.”
And fellow Labour MP Margaret Hodge – parliamentary chair of the Jewish Labour Movement – said Mr Corbyn had “refused to himself accept the findings of the EHRC report, refused to apologise for his actions and refused to take any responsibility”.
What is the party whip?
MPs sitting in the House of Commons on behalf of a party are given what is called “the party whip”.
It allows them to represent their chosen party and stand for them in elections, as well as ensuring they receive a letter about forthcoming parliamentary business, detailing the position the party is taking.
Having the whip taken away is considered a serious punishment by a party.
While the MP can keep their seat in the House, they are classed as an independent and cannot run for the party in the next election, unless that whip is restored.
But allies of Mr Corbyn have urged Sir Keir to change his mind immediately.
Mr McCluskey, whose Unite union is one of Labour’s biggest financial backers, said he was “astonished”, adding: “The continued persecution of Jeremy Corbyn, a politician who inspired millions, by a leadership capitulating to external pressure on party procedures risks destroying the unity and integrity of the party.”
Mr Lavery, who served as Labour chairman under Mr Corbyn, leader from 2015 until earlier this year, told the BBC News Channel: “This is a strange way of rebuilding trust.”
He added: “Does this mean that, for the first time in Labour Party history, we have a leader who overrules who overrules democratic processes… because of what he sees as the right decision?”
Mr Lavery also asked: “Is this political persecution against the former leader?”
While many Labour MPs have supported Sir Keir’s decision, 28 MPs and four peers have signed a statement calling for a “swift reversal”.
Former shadow chancellor John McDonnell, a long-time Corbyn ally, called Sir Keir’s decision “just plain wrong” and likely to cause “more division and disunity in the party”.
The EHRC’s report found Labour had broken the law over its handling of anti-Jewish racism complaints by party members during Mr Corbyn’s tenure.
On Tuesday, Mr Corbyn attempted to clarify his position in public, saying that “concerns about anti-Semitism are neither ‘exaggerated’ nor ‘overstated'”.
Thelma Walker, Labour MP for Colne Valley, West Yorkshire, from 2017 to 2019, quit the party on Wednesday, saying it had been a “privilege” to work with the former leader.
Mr McDonnell responded by saying: “When Thelma Walker, one of Labour’s loyalest of the loyal, feels so strongly that she resigns, then it’s time voices like hers are listened to.”