It is an astonishing statistic: Some 87 percent of British Jews believe that Jeremy Corbyn—one of two men who could be prime minister in a few days’ time—is anti-Semitic.

How did we get here? Corbyn’s party, Labour, has strong connections with the Jewish community, dating back to its earliest days. Yet a deep distrust has developed between the two since he became Labour leader in 2015, and the issue has dogged Corbyn throughout this election campaign.

The litany of alarming incidents is well rehearsed: Corbyn’s support for an artist who drew a mural depicting hook-nosed bankers getting rich on the backs of the poor. (He said he had not looked properly at the mural.) His assertion in 2013 that British Zionists “don’t understand English irony.” (He said he would now be more careful about using the word Zionist, because it had been “hijacked by antisemites as code for Jews.”) Labour’s refusal to adopt in full an internationally recognized description of anti-Semitism. Each of these individual incidents was made more toxic by the party’s slow handling of complaints filed by Jewish members. During the campaign, Corbyn refused four times to apologize for the distress caused to the Jewish community when questioned on camera by the BBC’s Andrew Neil—a particularly odd decision, because he has done so previously. The party is currently being investigated over allegations of institutional anti-Semitism by Britain’s Equality and Human Rights Commission.

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.

Then came Corbyn. To understand the near-complete breakdown of the relationship between Labour and the Jewish community, it is necessary to understand the character and background of the party’s leader. Corbyn was first elected in 1983, and served for more than three decades in relative obscurity, turning up at marches against colonialism, American imperialism, and the Iraq War with more enthusiasm than he showed for parliamentary debates over legislation. Then in the autumn of 2015, he stood for leader, and the membership—battered by two election defeats and tired of making accommodations with Conservative austerity policies—swept behind him. He triumphed without having the support of the party’s institutions, the trade unions that fund it, or the majority of its members of Parliament.

From the start, that led to his team adopting a bunker mentality (with good cause, Corbyn’s supporters would say, given the internal opposition to his leadership). In 2016, after he only half-heartedly campaigned to remain in the European Union, his own MPs tried to topple him. They failed, and Corbyn used the opportunity to consolidate his position. His backers now control the party’s rule-making board, the National Executive Committee, and hold top management positions. Labour’s manifesto for the upcoming election has been written in his left-wing image: Pledges include offering free university tuition to all students, cutting train fares by a third, and partially nationalizing broadband provision.

Unfortunately, that bunker mentality has also exacerbated the party’s problem with anti-Semitism. Genuine concerns on the part of some members have been interpreted as bad-faith attacks designed to derail the Corbyn project. The most visible effort to tackle the problem, a report into the issue by the former think-tank director Shami Chakrabarti, prompted allegations of a whitewash. The report, published in June 2016, began: “The Labour Party is not overrun by antisemitism, Islamophobia or other forms of racism.” Three months later, Chakrabarti was made a Labour peer.

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As Labour leader, Corbyn was always going to face questions about his attitude to Israel; for many activists in his section of the left, Zionism is a form of Western colonialism comparable to apartheid. Notably, the definition of anti-Semitism that Corbyn refused to accept last year focused on Israel. (It stated that it was unacceptable to compare Israel’s actions to those of the Nazis, accuse Jewish citizens of “divided loyalties,” or call the existence of Israel a racist endeavor.) The saga revealed that many Britons have no idea that anti-Semitism does not comprise only abuse hurled at Jewish people, and little appreciation of the vital distinction between, say, criticism of illegal settlement-building and suggestions that Israel has no right to exist at all.

Disproportionate hatred of Israel is one strand of left-wing anti-Semitism. The other is the conspiracist turn, turbocharged by social media, which gains succor from attacks on “the elite,” “the 1 percent,” “the mainstream media,” and “billionaires.” Corbyn has made such attacks a key part of Labour’s appeal, adopting the slogan “For the many, not the few.” The trouble is that while all of these are superficially innocent phrases—as well as useful ways of describing a world in which wealth and opportunities are unequally distributed—it is clear that some supporters hear them as a dog whistle. Jews have long been accused of running shadowy cabals: References to the Bilderberg Group, the Rothschilds, and George Soros are staples of online conspiracy theories. This tendency intersects with the anti-colonialist view of Israel, Mike Katz, the chair of the Jewish Labour Movement, which represents Jewish socialists, told me. “In the way people talk about ‘who’s bankrolling Zionists?’ Jews have always been accused of having divided loyalty,” he said. “Prior to Israel, it was some shadowy world government.”

Over time, these concerns have built up. Research published in October in the journal Electoral Studies showed that “the historical association of the British Jewish community with the Labour party is a thing of the past.” This year, Shinwell’s great-niece, Luciana Berger, herself a Labour MP since 2010, left the party. She said she could no longer tolerate the hatred and threats she had received for being Jewish, and the lack of support she felt she had gotten from her local party and the leadership.

A single borough in North London, Barnet, is home to a fifth of all British Jews. That means the purely electoral impact of Labour’s anti-Semitism crisis is limited. The only seat that is really seeing an “anti-Semitism effect,” as the pollster Peter Kellner put it to me, is Finchley and Golders Green, an area of Barnet where Berger is standing (as a Liberal Democrat). Conservatives won it at the past three elections, and Labour at the three before that. Berger hopes to break the duopoly, helped by the fact that Labour support there has dropped from 44 percent at the last election in 2017 to 19 percent now. It would be a blow to Labour if she did win: The party is trailing the Conservatives in national polls and every seat counts.

Yet perhaps because Britain’s Jews are so few in number, their fears are all the more potent: In his Times article, Mirvis identified a worry that repeatedly came up when I talked with members of the British Jewish community over the past several weeks—a persistent sense that their concerns are dismissed as driven by a right-wing or anti-Corbyn agenda. “We have been treated by many as an irritant, as opposed to a minority community with genuine concerns,” the chief rabbi wrote. (Responding to Mirvis, a Labour Party spokesman said: “Jeremy Corbyn is a lifelong campaigner against anti-Semitism and has made absolutely clear it has no place in our party and society, and that no one who engages in it does so in his name. Anti-Semitism complaints account for about 0.1 percent of the Labour Party membership, while polls show anti-Semitism is more prevalent among Conservative than Labour supporters.”)

“I consider myself to be left-wing,” Peter Mason, secretary of the Jewish Labour Movement, told me. “There’s not much in the manifesto I disagree with. But because I talk about anti-Semitism and I’m Jewish, I’m pigeonholed as being more right-wing than Genghis Khan.”

The sense that Jews are not being listened to—by Labour or by the wider population—drove Stephen Pollard, the editor of The Jewish Chronicle, to publish a front-page editorial about Corbyn last month, addressed specifically to non-Jews. It ended: “If this man is chosen as our next prime minister, the message will be stark: that our dismay that he could ever be elevated to a prominent role in British politics, and our fears of where that will lead, are irrelevant.”

Pollard is a well-known right-wing commentator, so I put the accusation to him: It was no hardship for him to condemn Corbyn, given their very different political beliefs. “We’re not in the business of telling people how to vote,” he replied, noting that he would be voting for the centrist Liberal Democrats. “We were very careful simply to say: All we ask is, when you cast that vote, think about this thing.” The response from readers, he said, was huge, and 95 percent positive.

Of course, Labour is not the sole reason for rising Jewish concerns about anti-Semitism in Britain and elsewhere. Both the far right and Islamist extremists have carried out attacks on Jews in recent years. In 2015, a man who pledged allegiance to the Islamic State conducted a siege of a kosher Paris supermarket. Last year, a gunman killed 11 people at the Tree of Life synagogue in Pittsburgh. Of those jailed for threats against Berger, two had links to the far right.

Still, the background hum of anti-Jewish hatred means it is even more important to many British Jews that political parties are sensitive to their concerns. “It’s not the idea there’s going to be cattle trucks or Nuremberg-type laws passed,” Pollard said. His worry, he added, was that in Corbyn, Britain would have “a prime minister who—at the most charitable level—cared so little about anti-Jewish racism.”

The crisis is now so deep that it has become hard for British Jews to state publicly that they support the Labour Party. Survation found that although Jews voted 2 to 1 to remain in the European Union, 78 percent prefer a hard Brexit to a Corbyn government. “The last four years have been grueling,” Mason added. “In your local party, you are constantly expected to justify the existence of anti-Semitism, told that you’re a liar, you’re not really Labour.” Katz has had a similar experience. When he was standing for election in Hendon, North London, in 2017, he was subjected to anti-Semitic abuse on Twitter—one user, purporting to be a Labour supporter, said the prospective Labour MP did not back Corbyn, and instead of Hendon, would “represent Tel Aviv.”

The partisan overtones make this debate even more toxic. Some left-wing Jews I spoke with said their voices, and their concerns, were being co-opted by the right, out of opportunism. They felt it was now hard to say that, despite its troubles, Labour was still the best choice at this election—and that other political parties had their own failings on race and racism. On November 22, Jonathan Lis, who is the deputy director of the think tank British Influence, wrote an article in The Guardian explaining why, as a Jewish person, he was voting Labour. “Nobody can identify any specific policies or threats made by the Labour leadership against Jewish people,” he wrote, adding that while Corbyn had been “careless,” it was “an enormous leap … to claim that he is personally antisemitic.”

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Did Lis feel defensive about his decision to write the piece, I asked. “Yes!” he answered instantly, adding that members of his own family had criticized the article. “I’m not pitting anti-Semitism against the benefits of the Labour Party; that’s horrendous. But there has to be a way we can fight anti-Semitism in the Labour Party and fight for a progressive society.”

Lis, who is not a Labour member, said he was particularly angry at the way the issue had been jumped on by Labour’s political opponents. He noted that Johnson had written columns about women in burkas looking like letter boxes and that the Conservatives had deported members of “the Windrush generation” to countries they had left as children, because they could not produce paperwork showing their right to live in Britain. During the Brexit campaign, the Leave side (which Johnson supported) had stoked fears about Turkey joining the European Union—which would have given citizens of the Muslim-majority country the right to live in Britain. “The Nazis murdered four of my great-grandparents,” Lis tweeted hours after we met. “The Labour Party has fucked up on antisemitism. But nothing, nothing offends or enrages me more than people who have spent their entire careers promoting racist exclusionary politics presuming to defend my interests.”

For Mason, the overriding emotion is exhaustion. He grew up in public housing in the central English city of Leiceister and joined the Labour Party at 16, rising up to become the secretary of the Jewish Labour Movement and a member of Labour’s disciplinary board. He said he had dedicated 15 years of his life to the party, only to “get to the end—and it does feel like the end—and it’s like, I’ve wasted my life on a political project that doesn’t want me.” The Jewish Labour Movement decided it could not campaign for the party as a whole at this election; instead, it is canvassing for particular candidates who have been strong supporters. (Its submission to the outside investigators now looking at the issue provides examples of Jews in Labour being referred to as “traitors,” “Zios,” and “a cancer” by other members, adding: “The party’s attitude to anti-semitism is inevitably influenced by signals from its leader.”)

The breakdown of the relationship between Labour and the Jewish community is profound. It is a story that weaves in many themes of modern politics: anti-imperialism, internet conspiracy, Islamist extremism, polarization, social-media abuse, the rise of the hard left and hard right. At its heart, though, it is a story about belonging. Britain’s Jews are used to feeling that their safety is provisional, that they are not fully accepted, that they will always be treated as outsiders. The Labour Party now joins a long list of those who have let them down.