Jeremy Corbyn’s failure to tackle antisemitism makes him unfit to be prime minister, the Chief Rabbi has said in an unprecedented attack on the Labour leader.

Ephraim Mirvis said he had decided to break with convention and intervene in politics ahead of the general election because “the very soul of our nation is at stake”.

Mr Mirvis received high-profile backing from the Archbishop of Canterbury, the Most Rev Justin Welby, who said his intervention reflected the alarm felt by many in the Jewish community.

In a speech on race and faith in London, Mr Corbyn made no reference to the rabbi's comments, but issued a denunciation of antisemitism as "vile and wrong" and promised that it would not be tolerated in a Britain led by Labour.

He insisted that Labour was responding "rapidly and effectively" to allegations of antisemitism within its ranks and said that if he becomes prime minister, his door will be open to the Chief Rabbi and all other religious leaders to discuss their concerns and work with him on creating "a society that is respectful to all faiths".

Writing in The Times, Mr Mirvis rejected Labour’s claims that the party were dealing with the problem as “a mendacious fiction”.

And he claimed that the “new poison” of antisemitism that had taken root in the party was “sanctioned from the top”.

“Many members of the Jewish community can hardly believe that this is the same party that they called their political home for more than a century,” he wrote. “It can no longer claim to be the party of equality and anti-racism.

“How far is too far? How complicit in prejudice would a leader of Her Majesty’s opposition have to be to be considered unfit for office?

Protests against Labour antisemitism Show all 14 1 /14 Protests against Labour antisemitism Protests against Labour antisemitism Protesters clashed during the demonstration Reuters Protests against Labour antisemitism Members of the Jewish community hold a protest against Labour party leader Jeremy Corbyn and antisemitism in the Labour Party AFP/Getty Protests against Labour antisemitism Protesters hold placards and flags during a demonstration, organised by the British Board of Jewish Deputies for those who oppose antisemitism, in Parliament Square Reuters Protests against Labour antisemitism Hundreds of people gathered in Parliament Square to protest against antisemitism in the Labour Party EPA Protests against Labour antisemitism Labour MP Luciana Berger speaks during the protest PA Protests against Labour antisemitism A protester blows through a shofar during the demonstration Getty Protests against Labour antisemitism Members of London's Jewish community protest in support of Labour leader Jeremy Corbyn outside parliament EPA Protests against Labour antisemitism Labour MP John Mann speaks during a protest against antisemitism PA Protests against Labour antisemitism People protest against antisemitism in the Labour Party as Jewish community leaders have launched a scathing attack on Jeremy Corbyn, claiming he has sided with antisemites ‘again and again’ PA Protests against Labour antisemitism Labour politicians Stella Creasy and Chuka Umunna leave after attending the demonstration Getty Protests against Labour antisemitism A pro-Jeremy Corbyn protester holds a placard during a counter-protest Getty Protests against Labour antisemitism A support of the Labour Party hold up a placard during the demonstration Reuters Protests against Labour antisemitism Jeremy Corbyn supporters during the demo Reuters Protests against Labour antisemitism A protester holds up a sign reading ‘For the many, not the Jew’ AFP

“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 Chief Rabbi said that the overwhelming majority of British Jews were “gripped by anxiety” ahead of the general election on 12 December.

He wrote: “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?

“The Jewish community has watched with incredulity as supporters of the Labour leadership have hounded parliamentarians, members and even staff out of the party for challenging anti-Jewish racism. Even as they received threats, the response of the Labour leadership was utterly inadequate.”

The Archbishop of Canterbury responded: "That the Chief Rabbi should be compelled to make such an unprecedented statement at this time ought to alert us to the deep sense of insecurity and fear felt by many British Jews."

The Chief Rabbi asked the public to “vote with their conscience”. He added: “It is not my place to tell any person how they should vote. I simply pose the question: What will the result of this election say about the moral compass of our country?”

Luciana Berger, who quit Labour in February over the party’s alleged anti-Semitic prejudice and is standing as a Liberal Democrat in the election, called it an “unprecedented and devastating intervention”.

Speaking at the launch of his party's race and faith manifesto in London, Mr Corbyn said: "Antisemitism in any form is vile and wrong. It is an evil within our society, it is an evil that grew in Europe in the 1920s and 1930s and ultimately led to the Holocaust.

"There's no place whatsoever for antisemitism in any shape or form or in any place whatsoever in modern Britain and under a Labour government it will not be tolerated in any form whatsoever, I want to make that clear."

He added: "Where cases have been reported to us in the Labour Party, we have a rapid and effective system for dealing with it and that system is constantly under review to make sure it is rapid and it is effective. And we have an education programme within our party so that people can happened, how the Holocaust finally came about, what was the lead-up to it, what were the levels of racism that led to it, how was it the far right was able to rise."