London(CNN) The UK's Chief Rabbi has strongly criticized Labour leader Jeremy Corbyn over his handling of allegations of anti-Semitism, in an unprecedented intervention during the final weeks of the election campaign.
Writing in The Times newspaper, Ephraim Mirvis said "British Jews are gripped by anxiety" at the prospect of Labour forming the next government, following the general election on December 12.
Mirvis, who heads the United Hebrew Congregations of the Commonwealth, said Corbyn's claim that his party is doing all it can to tackle anti-Semitism is "a mendacious fiction."
He said the manner in which allegations of anti-Semitism within the Labour Party had been handled was "incompatible with the British values of which we are so proud."
"It is a failure to see this as a human problem rather than a political one. It is a failure of culture. It is a failure of leadership. A new poison -- sanctioned from the top -- has taken root in the Labour Party," he said.
In response to Mirvis' comments, the Labour Party said Corbyn was "a lifelong campaigner against anti-Semitism."
"A Labour government will guarantee the security of the Jewish community, defend and support the Jewish way of life, and combat rising anti-Semitism in our country and across Europe," a party spokesperson said.
The spokesperson rejected Mirvis' claim that there are "130 outstanding cases" of anti-Semitism involving the Labour Party, and said, "We are taking robust action to root out anti-Semitism ... with swift suspensions ... rapid expulsions and an education program."
Labour candidate for Birmingham Yardley Jess Phillips said on Twitter the "only response to the chief Rabbi that is moral is, "I'm sorry and I'll do whatever I possibly can to win back your community's trust." So that's what I will say."
But in an interview with the BBC on Tuesday night, Corbyn himself refused to apologize to the Jewish community following Mirvis' comments.
Asked four times if he would say sorry, the opposition leader instead said that a Labour government would protect "every community against the abuse they receive."
"I am determined that our society will be safe for people of all faiths. I don't want anyone to be feeling insecure in our society and our government will protect every community against the abuse they receive on the streets, on the trains or any other form of life," Corbyn said.
Labour peer Alf Dubs, who fled Nazi-occupied Czechoslovakia on a Kindertransport train shortly before the outbreak of World War II, defended Corbyn in an interview on BBC Radio 4 on Tuesday, saying he thought the Chief Rabbi "had gone a bit far."
He said the Labour Party was launching a race and faith manifesto on Tuesday, "which goes a long way towards meeting some of the criticisms the Jewish community has felt."
While he said he does not believe Corbyn is anti-Semitic, Dubs conceded that "things have happened under his leadership which should have been stopped way back."
But Dubs insisted Jews should not be afraid, as "there are many of us in the Labour party who will ensure that there is no fear for you."
Mirvis' statement comes as reports of anti-Semitic incidents spike in the UK, according to a report by the Community Security Trust (CST), a charity that monitors anti-Semitism in Britain.
Mirvis added: "How complicit in prejudice would a leader of Her Majesty's Opposition have to be to be considered unfit for office? Would associations with those who have incited hatred against Jews be enough? Would describing as 'friends' those who endorse the murder of Jews be enough? It seems not."
The Archbishop of Canterbury, Justin Welby, aired his support for Mirvis' intervention on Tuesday. "Everyone in our country is entitled to feel safe and secure," Welby wrote in a statement posted on Twitter.
"As a Church, we are very conscious of our own history of anti-Semitism," Welby wrote. "None of us can afford to be complacent. Voicing words that commit to a stand against anti-Semitism requires a corresponding effort in visible action."
The Muslim Council of Britain (MCB), the largest group representing Muslims in the UK, issued a statement in support of Mirvis's comments.
"Today's statement by the Chief Rabbi highlights the real fear many British Jews have, regarding the unacceptable presence of anti-Semitism in Britain and in politics today," a MCB spokesperson said.
"We agree with the Chief Rabbi's observation that 'some politicians have shown courage but too many have sat silent,'" the statement said.
But the group also highlighted allegations of Islamophobia within the Conservative Party; the group said the Tories "have approached Islamophobia with denial, dismissal and deceit."
"British Muslims ... will listen to the Chief Rabbi and agree on the importance of voting with their conscience," the MCB statement added.
UK Prime Minister Boris Johnson told journalists on Tuesday that he did not agree with the claim that the Conservatives had approached Islamophobia with denial, dismissal and deceit, and added: "What we do in the Tory Party is when anybody is guilty of any prejudice or discrimination against another group, then they're out first bounce."
On Tuesday, fellow party member and Chancellor Sajid Javid also refused to criticize Johnson for derogatory remarks he made about Muslim women.
Johnson had written in his weekly column for the Daily Telegraph newspaper last year that women who choose to wear the full-face veil resemble "letter boxes" and "bank robbers." He also branded the conservative Islamic dress "oppressive."
Javid told reporters that Johnson had "explained why he's used that language," and that the article "was to defend the right of women, whether Muslim women or others to wear what they like, so he's explained that and I think he's given a perfectly valid explanation."
The Chief Rabbi's condemnation of Corbyn and his leadership could damage Labour's hopes of ousting Johnson and his Conservative Party from power.
Corbyn, who became Labour leader in 2015, has long been an outspoken critic of Israel and a campaigner for Palestinian rights.
He was widely condemned for being present at a 2014 wreath-laying ceremony at a cemetery in Tunisia, where members of Black September -- the Palestinian terrorist organization which carried out the 1972 Munich attack, in which 11 Israeli Olympians were killed -- are buried.
Questions over whether the Labour Party contains anti-Semitic elements have been on the rise in recent years and, at best, Corbyn has been accused of turning a blind eye to the resurgence of anti-Semitism within British politics and the party itself.
Corbyn acknowledged in 2018 "that anti-Semitism has occurred in pockets within the Labour Party" and apologized for the hurt caused.
In his Times article, Chief Rabbi Mirvis refused to tell people who to cast their ballot for, but urged them to vote with their conscience.
"I simply pose the question: what will the result of this election say about the moral compass of our country?" He wrote. "Be in no doubt, the very soul of our nation is at stake."