The findings aired Wednesday by the service’s flagship investigative television program “Panorama” represent the largest-scale journalistic focus on Labour’s anti-Semitism and are significant because they seem to confirm allegations that earlier this year made Labour the subject of an official probe by the United Kingdom’s watchdog on racism.

The team of Jeremy Corbyn, Labour’s leader since 2015 and the man many hold responsible for the proliferation since that year of anti-Semitic hate speech in Labour’s ranks, repeatedly interfered in disciplinary cases, several Labour whistleblowers told the makers of the BBC program titled “Is Labour anti-Semitic?”

Labour denied that Corbyn’s team had intervened in disciplinary cases, saying the claims had been made by “disaffected former officials…who have always opposed Jeremy Corbyn’s leadership”. It accused the BBC of having “engaged in deliberate and malicious representations designed to mislead the public,” The Independent reported.

If the allegations of interference are correct, the revelation means Corbyn’s team has compromised Labour’s internal processes and ethics committee, strengthening the case for external action by the Equality and Human Rights Commission, which began its probe of Labour earlier this year. This could weaken the position of Corbyn, who is under growing pressure by critics from his own party.

Corbyn was personally copied into emails in which Jennie Formby, the party’s general secretary, appeared to promise to interfere in a case involving an activist who had claimed Jews were responsible for the slave trade, according to the BBC. In another case, Seumas Milne, Corbyn’s director of communications, told party staff they were “muddling up political disputes with racism” and said Labour needed to “review where and how we’re drawing the line.”

The reputation of the Labour Party “has been shredded by a Hard Left establishment that has proven apparently incapable of addressing the endemic racism within. Their reign must be quickly and efficiently ended,” Labour Against Anti-Semitism, an internal party group, wrote in a statement following the airing of the show.

The Board of Deputies of British Jews in a statement wrote that Panorama shows that Corbyn and his allies “are personally responsible for having turned a once-great, anti-racist party into a cesspit of antisemitism.”

To the Campaign Against Antisemitism, a nonprofit, “The charade of Jeremy Corbyn as an anti-racist activist has been blown apart. Mr Corbyn’s support for antisemites and his team’s protection of antisemites demonstrate that Mr Corbyn himself is an antisemite who is unfit to hold any public office,” its chief executive, Gideon Falter, wrote.

On Tuesday, three lawmakers from Labour, two of them Jewish, resigned from the party over its anti-Semitism problem, prompting speculation that the timing was connected to the expected findings of the hour-long expose of the BCC.

One of the leavers, Leslie Arnold Turnberg, said Corbyn and “his circle are anti-Semitic, having never once made the right judgement call about an issue reflecting deep prejudice,” Turnberg wrote. Anti-Semites were “shielded”, while “serious party members are thrown out unceremoniously,” he said. “The experience of life in the party has become sickening.”

Corbyn’s supporters have dismissed the charges and allegations that the problem owes to Corbyn’s anti-Israel stance. In 2009, he called Hezbollah and Hamas his friends, adding that the Hamas is “an organization that is dedicated towards the good of the Palestinian people and bringing about peace and social justice.”

But his critics allege that Corbyn had dabbled in classic anti-Semitism independent to Israel, also in his 2013 defense of a London mural showing Jewish bankers playing Monopoly on the backs of dark-skinned men. He said he had failed to notice the anti-Semitic message when he endorsed the controversial painting.