LONDON — In a decisive break with the hard-left wing of Britain’s opposition Labour Party, its new leader dismissed a senior lawmaker on his leadership team Thursday for having shared an article online that the party said contained an anti-Semitic conspiracy theory.
The dismissal by the new Labour leader, Keir Starmer, represented a pronounced shift from the handling of allegations of anti-Semitism under Jeremy Corbyn, his predecessor, who led the party to a catastrophic election defeat in December as voters expressed anger in part over the party’s sluggish response to anti-Semitism in its ranks.
It also amounted to a broader rebuke of Labour’s hard left. The lawmaker who was dismissed, Rebecca Long-Bailey, was the member of Mr. Starmer’s team most closely identified with Mr. Corbyn’s leadership. Her inclusion in the “shadow” cabinet — a group consisting of the most senior opposition lawmakers — had been seen as an attempt to unite competing factions within the party.
Mr. Starmer, who comes from the more moderate wing of Labour, asked Ms. Long-Bailey to step down from his leadership team after she had praised an English actress who, without citing any evidence, blamed training by Israeli security services for the tactics used in the killing of George Floyd by a police officer in Minneapolis. Mr. Floyd’s death last month was a catalyst for widespread protests in the United States and elsewhere over police brutality against African Americans and other people of color.
“The tactics used by the police in America, kneeling on George Floyd’s neck, that was learned from seminars with Israeli secret services,” the actress, Maxine Peake, told the Independent, a British news outlet, in an article about her published on Thursday.
Ms. Long-Bailey posted the article on Twitter, saying “Maxine Peake is an absolute diamond.”
For many readers, the implication that Israel played a role in Mr. Floyd’s death at the hands of the police was plainly anti-Semitic. Ms. Long-Bailey’s defenders pointed to an article published by Amnesty International that discussed trips by American law enforcement officials to Israel for training. The article did not mention the police department in Minneapolis or the use of neck restraints.
“The article Rebecca shared earlier contained an anti-Semitic conspiracy theory,” a spokesperson for Mr. Starmer said in a statement. “As leader of the Labour Party, Keir has been clear that restoring trust with the Jewish community is a number one priority. Anti-Semitism takes many different forms and it is important that we all are vigilant against it.”
Before her dismissal, Ms. Long-Bailey, who had led the party’s handling of education matters in the shadow cabinet, said on Twitter that her posting of the article “wasn’t intended to be an endorsement of all aspects” of it. She later said that the wording of that clarification had been approved in advance by Mr. Starmer’s office, but that his office subsequently told her to remove all her posts about the article. Ms. Long-Bailey will remain in Parliament.
“I had asked to discuss these matters with Keir before agreeing what further action to take, but sadly he had already made his decision,” she wrote on Twitter. “I am clear that I shall continue to support the Labour Party in Parliament under Keir Starmer’s leadership.”
The Board of Deputies of British Jews said that it had asked Ms. Long-Bailey to apologize but that her response was “frankly pathetic.” The organization commended Mr. Starmer’s decision to dismiss her.
“There can be no space for this sort of action in any party,” the organization’s president, Marie van der Zyl, said in a statement, “and it is right that after so many challenging years Labour is now making this clear under its new leader.”
John McDonnell, a Labour lawmaker who led the party’s handling of economic issues under Mr. Corbyn, defended Ms. Long-Bailey, saying the comments in the news article fell within the bounds of acceptable criticism of Israel.
“Throughout discussion of anti-Semitism it’s always been said criticism of practices of Israeli state is not anti-Semitic,” he wrote on Twitter. “I don’t believe therefore that this article is or @RLong_Bailey should’ve been sacked. I stand in solidarity with her.”
In the article shared by Ms. Long-Bailey about Ms. Peake, the English actress also defended Mr. Corbyn, an implicit rebuke to Mr. Starmer who is trying to turn a page on his predecessor’s leadership. The actress said that people choosing to rejoin Labour because of Mr. Starmer should be ashamed. Ms. Long-Bailey competed with Mr. Starmer to take over leadership of the party, positioning herself as the hard left’s best hope to keep control of Labour.
Britain’s Equality and Human Rights Commission has been conducting a yearlong investigation into anti-Semitism within Labour. Mr. Starmer, who was elected leader of the party in April, has promised to implement its recommendations.