Unite general secrtary Len McCluskey has waded into the row over Labour antisemitism, accusing Jewish community leaders of "truculent hostility" and "refusing to take yes for an answer".

The close ally of Jeremy Corbyn claimed Jewish groups had shown "an utter refusal to engage in dialogue" and were guilty of "petulant trolling".

In an explosive article likely to fuel the bitter dispute over Labour antisemitism, Mr McCluskey said he did not understand the "motives" of Jewish community leaders and urged them to "dial down the rhetoric".

But he said the party needs to "move on" and joined calls for Labour to adopt the full version of an internationally-recognised definition of antisemitism that has been the subject of a major row in recent weeks.

Mr McCluskey is one of Mr Corbyn's closest allies and a vocal supporter of the Labour leadership.

Writing for HuffPost, the Unite general secretary claimed Labour had agreed to all the requests made by Jewish community leaders.

He wrote: "I am at a loss to understand the motives of the leadership of the Jewish community – the Board of Deputies, the Jewish Leadership Council and the Jewish Labour Movement.

"What is the response from the leading Jewish community organisations to this record of reaching out, of understanding, and of action? Intransigent hostility and an utter refusal to engage in dialogue about building on what has been done and resolving outstanding difficulties."

He also accused three Jewish newspapers of "a thoroughly irresponsible act of fear-mongering" in relation to a joint front page story accusing Mr Corbyn of posing "an existential threat to Jewish life" in the UK, and said the Board of Deputies of British Jews was guilty of "petulant trolling" for claiming Mr Corbyn had gone "into hiding" over the summer.

Mr McCluskey said: "I therefore appeal to the leadership of the Jewish community to abandon their truculent hostility, engage in dialogue and dial down the rhetoric, before the political estrangement between them and the Labour Party becomes entrenched.

"Surely a community leadership which had time to publicly challenge the BBC over a news headline critical of the Israeli Defence Forces in Gaza has the time to meet the Leader of the Opposition?"

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

In response, a Board of Deputies spokesperson said: "We note that Len McCluskey has advocated the adoption of the full IHRA definition of antisemitism and its illustrative examples.

"However, his attack on the Jewish community is both unfair and unwarranted. We have had a deluge of words from the Labour leadership. It is about time that the party resolved this crisis by taking the firm and decisive action which the communal leadership set out for them in detail months ago. They have so far failed to do what is right.”

Mr McCluskey also launched a scathing attack on Chuka Umunna over an article for The Independent in which the Streatham MP said Labour had a problem with "institutional antisemitism".

The Unite leader wrote: "Chuka Umunna’s article this week was an exercise in Blairite triangulation – and cynicism. He equates Tory anti-Muslim racism with alleged “institutional antisemitism” in Labour, despite providing no serious evidence that the latter exists.

"Given the paucity of evidence that he actually produces to sustain his charge that he is a member of an “institutionally antisemitic” party, it is fair to ask whether Umunna is merely exploiting the latest episode to justify his moves to breakaway from Labour, the plotting for which has been widely reported elsewhere."

Mr Umunna immediately hit back: "I stand by what I've said on racism in the Labour Party and won't be bullied into silence, not least because my family have experienced racism too. Jeremy Corbyn himself has said it is a problem Labour has not properly dealt with. If Len McCluskey doesn't like that, so be it.