A Labour candidate who had apologized for liking an anti-Semitic post on social media narrowly won a closely watched by-election for the British Parliament, results on Friday showed.

Lisa Forbes squeaked past Brexit Party candidate Mike Green in the special election in the eastern English city of Peterborough Thursday, as the new Euro-skeptic party helmed by anti-EU populist Nigel Farage failed to win its first seat in Britain’s parliament.

Forbes had drawn criticism earlier this week after it emerged she had liked a Facebook post that said British Prime Minister Theresa May had a “Zionist Slave Masters agenda.”

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She also commented: “I have enjoyed reading this thread so much” on a post that repeated the conspiracy theory that the Mossad and CIA are behind the Islamic State terror group.

In response, the Jewish Labour Movement said it would not campaign for her.

Forbes said it was a misunderstanding and apologized, adding that she would nevertheless take anti-Semitism awareness training.

However, a joint statement by the Board of Deputies of British Jews, the Jewish Leadership Council and the Community Security Trust said this week that her excuse that she had not seen the anti-Semitic content “stretches the limits of credulity, especially given the high profile problems in Labour and the previous anti-Semitism scandals in Peterborough Labour circles.”

Forbes had also signed a letter opposing Labour’s adoption of the International Holocaust Remembrance Association’s definition of anti-Semitism, saying members should be free to criticize Israel’s “system of apartheid and ongoing ethnic cleansing,” according to the Jewish Chronicle. The letter expressed backing for boycotts of Israel.

The Forbes revelations were the latest scandal to rock Labour, which has been dogged by allegations of harboring anti-Semitic elements, driving many Jews away from a party once considered their natural home.

The Labour Against Antisemitism group called her election a “dark day,” and urged the party’s leadership to suspend her. It said it had expected party members to distance themselves from Forbes once the social media activity became public.

“Instead we witnessed the unedifying spectacle of dozens of Labour MPs — many of whom moderates, who had signed a letter of solidarity with the Jewish Labour Movement as recently as March — streaming up to Peterborough over the last few days to support a candidate who should have been taken off the ballot paper on Sunday,” the group said.

A number of Labour MPs who have been critical of the party’s role in tackling anti-Semitism also expressed discomfort with Forbes’s win.

Margaret Hodge said she had raised her concerns with the party’s leadership.

“Seriously mixed feelings about the Peterborough result. I never want to see Nigel Farage’s party in Parliament. But Lisa Forbes & the Labour Party have a lot to answer for. We must learn lessons & never have a repeat of this,” she tweeted.

“I didn’t want to see the Brexit Party win, but it is no good to see Labour people demanding loyalty on the basis of being the lesser of two evils. There is no hierarchy of racism or prejudice. Antisemitism must never become normalised or more politically acceptable than any other form of discrimination,” wrote MP Wes Streeting. “I’ve given up hope that this Labour leadership can prove me wrong, but I have not given up hope that the new MP for Peterborough can be true to her apology and show genuine contrition.”

The Peterborough poll was triggered after the sitting MP, Fiona Onasanya, was dumped by voters after being jailed for lying over a speeding offence.

Forbes won 30.9 percent of the vote, beating Greene, who took 28.9 percent, by less than 700 votes. Paul Bristow of the ruling Tory party came in third with 21.3%.

Shadow Transport Secretary Andy McDonald told the BBC he was “discomfited” with Forbes’s anti-Semitic social media activity, but noted that she had apologized.

Labour leader Jeremy Corbyn said that the result “shows that despite the divisions and deadlock over Brexit, when it comes to a vote on the issues that directly affect people’s lives, Labour’s case for real change has strong support across the country.”

The Brexit Party had been heavy favorites to win the Leave-voting seat, but despite losing, their performance will still be a concern to the two main parties.

Labour’s vote share fell by 17 percent from 2017, and was the lowest ever to win a British by-election, while the Conservatives plunged by 25 percent.

Leading pollster John Curtice told the BBC said the result showed the country was now in a “different political world.”

Farage, who has called for Britain to leave the bloc without a deal, said last weekend while campaigning he saw the by-election as “the opportunity for the next chapter in this great story.”

“A lot of constituencies are now looking at four party politics and perhaps in others five party politics,” Farage said.

May is stepping down after delaying Brexit twice as she tried and failed to get her EU divorce deal through parliament.