Jeremy Corbyn has declared that left-wing anti-semitism is “the socialism of fools” and vowed to fast-track a Labour programme of anti-racism education to root out the problem.

In a letter to Jewish groups, the Labour leader also apologised personally for the hurt caused by his own apparent endorsement of a mural that has been condemned for spreading Jew-hating propaganda.

Corbyn’s move came as the Board of Deputies of British Jews and the Jewish Leadership Council staged a demonstration in Parliament Square protesting what they saw as his repeated failures to tackle anti-semitism.

The two groups handed a scathing letter to the Parliamentary Labour Party chairman John Cryer, which claimed “again and again, Jeremy Corbyn has sided with anti-Semites rather than Jews”.

But in his own letter in response, the Labour leader declared that he was a “militant opponent of antisemitism” and their ally in the fight against it. He offered to meet the two groups as soon as possible.

The issue flared up within minutes as Labour MPs made public speeches in Parliament Square and the weekly PLP meeting urging much tougher action.

Tony Blair told BBC’s Newsnight that Corbyn was not personally anti-semitic but he and others around him didn’t “understand the seriousness of the problem”

He also gave his most detailed apology for having suggested that the East End mural, which depicted Jewish financiers getting rich on the backs of the poor, should not be removed from a site in east London.

“While the forms of antisemitism expressed on the far Right of politics are easily detectable, such as Holocaust denial, there needs to be a deeper understanding of what constitutes antisemitism in the labour movement. 

“Sometimes this evil takes familiar forms – the east London mural which has caused such understandable controversy is an example. 

“The idea of Jewish bankers and capitalists exploiting the workers of the world is an old antisemitic conspiracy theory. This was long ago, and rightly, described as ‘the socialism of fools’. 

“I am sorry for not having studied the content of the mural more closely before wrongly questioning its removal in 2012.”

The phrase ‘Socialism of Fools’ was deployed by the German Social Democrats in the late 19th century to describe fellow socialists who mixed opposition to capitalism with conspiracy theories about Jewish bankers.

In his strongest statement to date on the issue, Corbyn made explicit for the first time that while criticism of Israel over its “dispossession of the Palestinian people…cannot be avoided”, some of that criticism is infused with anti-Jewish racism.

“Comparing Israel or the actions of Israeli governments to the Nazis, attributing criticisms of Israel to Jewish characteristics or to Jewish people in general and using abusive phraseology about supporters of Israel such as “Zio” all constitute aspects of contemporary antisemitism.

“And Jewish people must not be held responsible or accountable for the actions of the Israeli government.”

He went to say he was “sincerely sorry for the pain which has been caused, and pledge to redouble my efforts to bring this anxiety to an end”.

Crucially, Corbyn added that “I acknowledge that antisemitic attitudes have surfaced more often in our ranks in recent years, and that the Party has been too slow in processing some of the cases that have emerged”.

His letter also conceded that full implementation of the recommendations of the Chakrabarti report into alleged anti-semitism was “overdue”.

He promised to “speed up procedures, to deal with cases of antisemitic abuse or attitudes”.

But some of his critics pointed out that it was nearly two years since the Chakrabarti inquiry concluded.

Danny Stone, Director of the Antisemitism Policy Trust, told HuffPost: “What a shame that less than an hour before the Jewish community gathers to protest we have seen the first example of a proper, detailed apology and commitment to specific action from the Labour leader’s office.

“Education and implementation of the Chakrabarti report are simple steps. Making systemic changes is more difficult and it is for Labour to prove it can do this through actions, Not words.”

Speaking to Newsnight, Blair said:  “I don’t believe he is personally anti-semitic, no I don’t actually, but I do believe that he and the people around him particularly around him do not understand the seriousness of this problem.

“It’s got beyond the stage where words will solve this. He’s going to have to show that he really understands the issue, that the people round him really understand it, and that he’s prepared to act on it.”

Asked if he wasn’t conflating his own hawkish stance on foreign policy with the issue, Blair replied: “What I say to that is very simple – you can be anti the policy of any one Government in Israel – that’s different from being anti the state of Israel, anti its existence, and when people are in that position it very quickly trends across into anti Semitism.” 

The full text of Corbyn’s letter follows:

Dear Jonathan and Jonathan,

Thank you for your letter to the Labour Party concerning antisemitism issued as a press statement last night.

First of all, let me acknowledge the anger and upset that provoked it, and repeat my offer of an urgent meeting to discuss the issues you have raised as soon as possible.

I stated yesterday, and repeat today, that I will not tolerate any form of antisemitism that exists in or around our party and movement.  I am committed to eliminating antisemitism wherever it exists. 

As I told the Labour Party conference in 2016, antisemitism is an evil that led to the worst crimes of the 20th century. Prejudice and hatred of Jewish people has no place whatsoever in the Labour Party, and every one of us has a responsibility to ensure it is never allowed to fester in our society again. 

I recognise that antisemitism has surfaced within the Labour Party, and has too often been dismissed as simply a matter of a few bad apples. This has caused pain and hurt to Jewish members of our Party and to the wider Jewish community in Britain.  I am sincerely sorry for the pain which has been caused, and pledge to redouble my efforts to bring this anxiety to an end.

While the forms of antisemitism expressed on the far Right of politics are easily detectable, such as Holocaust denial, there needs to be a deeper understanding of what constitutes antisemitism in the labour movement.  Sometimes this evil takes familiar forms – the east London mural which has caused such understandable controversy is an example.  The idea of Jewish bankers and capitalists exploiting the workers of the world is an old antisemitic conspiracy theory. This was long ago, and rightly, described as “the socialism of fools.”  I am sorry for not having studied the content of the mural more closely before wrongly questioning its removal in 2012.

Newer forms of antisemitism have been woven into criticism of Israeli governments. Criticism of Israel, particularly in relation to the continuing dispossession of the Palestinian people, cannot be avoided. Nevertheless, comparing Israel or the actions of Israeli governments to the Nazis, attributing criticisms of Israel to Jewish characteristics or to Jewish people in general and using abusive phraseology about supporters of Israel such as “Zio” all constitute aspects of contemporary antisemitism. And Jewish people must not be held responsible or accountable for the actions of the Israeli government.

The Labour Party has always opposed antisemitism, old and new, and always will.  We are proud of our deep historical links with Jewish communities, and to have fought alongside generations of Jewish men and women against fascism, prejudice and discrimination. This is a part of our common heritage from which we will never be separated.  But I acknowledge that antisemitic attitudes have surfaced more often in our ranks in recent years, and that the Party has been too slow in processing some of the cases that have emerged. Early action has nevertheless been taken, and we will work to speed up procedures, to deal with cases of antisemitic abuse or attitudes. 

I am committed to making our Party a welcoming and secure place for Jewish people. Zero tolerance for antisemites means what it says, and the Party will proceed in that spirit. That demands among other things the overdue full implementation of the recommendations of the Chakrabarti report, including a programme of political education to increase awareness and understanding of all forms of antisemitism. 

The battle against antisemitism should never become a party political issue.  It must unite all of us if we are both to honour the memory of the victims of the bestial crimes of the 20th century and build a future of equality and justice for all.

In that spirit, I must make it clear that I will never be anything other than a militant opponent of antisemitism. In this fight, I am your ally and always will be.

Best wishes,

Jeremy Corbyn MP

Leader of the Labour Party