At the same time, the other plausible candidate to be the next prime minister—the Conservative leader, Boris Johnson—has faced his own questions over his use of racial epithets and his attitudes toward minorities. Racism directed at faith communities in Britain has therefore become a deeply partisan left/right issue: Any mention of “Labour anti-Semitism” is met with cries of “Tory Islamophobia.”

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Yet the question of anti-Semitism is also divisive within the left. Jewish voters I spoke with over the past several weeks told me of feeling as though the entire community had been “gaslit”—that the reality of anti-Semitism was being minimized by the party leadership—and that denying this reality had become a way to demonstrate loyalty to Corbyn and his radical anti-austerity agenda. This feeling is aggravated by persistent suggestions from the hard left that anti-Semitism is merely the pretext for a “smear campaign” against Corbyn and the left in general.

Britain’s Jewish community is small, about 284,000 people, or about 0.5 percent of the population, and heavily concentrated in a few areas of North London. That means many incidents that are widely noted by British Jews—such as Corbyn’s over-pronunciation of Jeffrey Epstein’s name as “Ep-schtein” in a televised debate—go unnoticed by the wider population. A Survation poll found that 39 percent of Britons overall believe Corbyn is anti-Semitic. While that is still a remarkably high number, it is far short of the consensus that has formed among Jews. The gulf has exacerbated the sense that their concerns are not being treated seriously by the rest of the population. As Britain’s chief rabbi, Ephraim Mirvis, wrote in The Times: “Just a few weeks before we go to the polls, the overwhelming majority of British Jews are gripped by anxiety. The question I am now most frequently asked is: What will become of Jews and Judaism in Britain if the Labour Party forms the next government?”

After the Labour Party was founded in 1900, Jewish workers in the East End of London were some of its first supporters, and the community produced several prominent Labour politicians over the 20th century, such as Manny Shinwell, who nationalized coal mining in 1946.

Though Labour’s dominance of the Jewish vote began to fray in more recent decades, Prime Ministers Tony Blair and Gordon Brown were strong supporters of British Jews—in 2006, Blair memorialized the resettlement of Jews in England by giving a speech in a synagogue, wearing a skullcap. Soon after becoming prime minister the following year, Brown visited Israel, stopping at the Yad Vashem museum in Jerusalem to commemorate the Holocaust, and announcing an initiative to overcome academic boycotts of the country.

By 2010, the year Brown was voted out of office, the community still leaned left compared with the population at large: In May that year, when a Conservative-led government was elected, British Jews were evenly split between Labour and the Conservatives. Brown’s successor as Labour leader, Ed Miliband, was a more controversial figure—in 2014, he voted to grant statehood to Palestine. Still, Miliband also visited Yad Vashem, met key members of the community, and spoke about his own Jewish (atheist) background.