Labour’s decision to suspend Jeremy Corbyn risks “chaos” and could cost the party the next election, one of the ex-leader’s most powerful allies has said.
Len McCluskey, general secretary of the Unite union, warned: “A split party will be doomed to defeat.”
Mr Corbyn was suspended after he refused to retract his claim that the scale of anti-Semitism in Labour had been “dramatically overstated” .
This followed a critical report on the problem during his time as leader.
The Equality and Human Rights Commission (EHRC) found Labour responsible for three breaches of the Equality Act:
Mr Corbyn’s successor as leader, Sir Keir Starmer, said the publication of the report, on Thursday, marked a “day of shame” for Labour and promised to implement its recommendations.
In his response to the EHRC’s findings, Mr Corbyn said he had “acted to speed up, not hinder the process” of dealing with complaints, but the scale of anti-Semitism within Labour had been “dramatically overstated for political reasons by our opponents inside and outside the party”.
Shortly afterwards Labour general secretary David Evans suspended Mr Corbyn, with the party saying this had happened “in light of his comments” and “his failure to retract them subsequently”.
The suspension will remain in place while an internal investigation into his remarks is carried out.
Sir Keir said he had been “very disappointed in Jeremy Corbyn’s statement and appropriate action has been taken, which I fully support”.
But Mr Corbyn, Labour leader from 2015 until April this year, appealed to the party to reinstate him.
Mr McCluskey, whose union – one of Labour’s biggest financial backers – has already reduced its funding for the party since Sir Keir took over, said: “This was a day for our party to move forward as one to defeat the evil of anti-Semitism.
“However, the decision to suspend Jeremy Corbyn has threatened that opportunity.”
He called the decision “an act of grave injustice which, if not reversed, will create chaos within the party and in doing so compromise Labour’s chances of a general election victory”.
Mr McCluskey called on Sir Keir “to work across the party on a fitting and unifying way forward, to unite our party behind the implementation of the EHRC’s important recommendations”.
And he urged members “angered by this suspension not to leave the party but to support moves to find a better way through”.
But Jewish Labour MP Dame Margaret Hodge said: “[The suspension] is the right decision following Corbyn’s shameful reaction to the EHRC report.”
Marie van der Zyl, president of the Board of Deputies of British Jews, said: “We welcome the decision of the Labour Party to suspend Jeremy Corbyn.
“Having presided over the descent of a proudly anti-racist party into a party that broke equalities law in its treatment of Jews, his shameless comments today showed that he remains part of the problem and is an obstruction to the resolution of the issue.”
And Labour deputy leader Angela Rayner told BBC Radio 4’s World at One: “Jeremy is a thoroughly decent man, but he has an absolute blind spot and a denial when it comes to some of these issues.”
But groups on the left of the Labour movement attacked the decision to suspend him.
The Socialist Campaign Group said it “firmly” opposed the move, adding: “We will work tirelessly for his reinstatement.”
And Momentum, among Mr Corbyn’s strongest backers, called him a “lifelong, dedicated anti-racist”, saying: “[His suspension] is a massive attack on the left by the new leadership and should be immediately lifted in the interests of party unity.”
For the Conservatives, Cabinet Office Minister Michael Gove has written to Sir Keir, saying he “seemingly found it much harder to find the moral character and backbone to do what was right” while serving in the shadow cabinet under Mr Corbyn.
The EHRC launched its investigation last year after receiving a number of complaints from organisations and individuals, including the Campaign Against Anti-Semitism and the Jewish Labour Movement.