A former chief rabbi has accused Jeremy Corbyn of the most offensive comments by a senior politician “since Enoch Powell”, after his criticism of British “Zionists”.

Jonathan Sacks made the most outspoken attack yet on the Labour leader, branding him “an antisemite” who has “given support to racists, terrorists and dealers of hate”.

“It was divisive, hateful and, like Powell’s speech, it undermines the existence of an entire group of British citizens by depicting them as essentially alien,” Lord Sacks said.

The condemnation deepens the crisis that has engulfed Mr Corbyn since his remarks at a pro-Palestinian event five years ago emerged last week.

He criticised “Zionists” who “don’t want to study history, and secondly, having lived in this country for a very long time, probably all their lives, don’t understand English irony either”.

Some Labour MPs reacted with horror, while Helen Grant, the Conservative MP, reported him to the parliamentary standards watchdog.

Now Mr Sacks has described the words as “the most offensive statement made by a senior British politician since Enoch Powell’s 1968 ‘Rivers of Blood’ speech”.

“We can only judge Jeremy Corbyn by his words and his actions,” he told the New Statesman magazine.

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

“He has given support to racists, terrorists and dealers of hate who want to kill Jews and remove Israel from the map.

“When he implies that, however long they have lived here, Jews are not fully British, he is using the language of classic pre-war European antisemitism.”

Mr Corbyn has defended his comments, insisting that he was referring to a specific group of “pro-Israel activists” and had not used the term Zionist as a “euphemism” for Jewish people.

He claimed he was “now more careful with how I might use the term ‘Zionist’ because a once self-identifying political term has been increasingly hijacked by antisemites as code for Jews”.

But Lord Sacks added: “When challenged with such facts, the evidence for which is before our eyes, first he denies, then he equivocates, then he obfuscates.

“This is low, dishonest and dangerous. He has legitimised the public expression of hate, and where he leads, others will follow.

In response, a Labour Party spokesperson said: “This comparison with the race-baiting Enoch Powell is absurd and offensive.

“Jeremy Corbyn described a particular group of pro-Israel activists as Zionists, in the accurate political sense – not as a synonym or code for Jewish people.

“Jeremy Corbyn is determined to tackle antisemitism both within the Labour Party and in wider society, and the Labour Party is committed to rebuilding trust with the Jewish community.”

Labour has been dogged by allegations of antisemitism all summer, sparked by a refusal to fully implement the International Holocaust Remembrance Alliance's (IHRA) examples to define antisemitism.

Mr Corbyn and his key advisers have resisted including any statement that says that claiming the Israeli state is a "a racist endeavour" is "denying the Jewish people their right to self-determination".

A meeting of the party's ruling national executive committee next week is expected to finally force Mr Corbyn to step into line with the wishes of his MPs.

However, critics fear the implementation of the IHRA definition and examples will be done in a way to prevent disciplinary action against anyone who breached the IHRA examples in the past.