Len McCluskey has accused Jewish leaders of showing “truculent hostility” towards Labour, as he called for the party to draw a line under the antisemitism row by adopting the International Holocaust Remembrance Alliance guidelines in full.

The Unite general secretary’s backing for the full IHRA definition, with all its examples, in Labour’s new code of conduct, will tip the balance on the party’s national executive committee, which is due to discuss the issue at its next meeting on 4 September.

“Clearly, it would have been far better for the party to have adopted at least 10 of the 11 IHRA examples in their original wording,” McCluskey wrote in an article for the Huffington Post.

“Not doing so – and particularly without adequate consultation – was insensitive and bound to lead to misunderstanding, and also served to distract attention from the real issues at stake. It would be for the best if all 11 were now agreed, so the party can move on,” he went on.

The union leader’s move came a day after the Guardian reported that Labour was edging towards adopting the IHRA code in full in the hope of ending a row that has damaged relations between the party and Jewish community organisations.

It also comes after two major other union bosses, the GMB leader Tim Roache and Unison’s Dave Prentis, called for Labour to accept the IHRA definitions, in articles published last week. Prentis had said that the row was “costing us the moral high ground” in politics.

But McCluskey also lashed out at the response of the Jewish community in recent months, accusing them of “refusing to take ‘yes’ for an answer”, as he listed a series of commitments made by Corbyn in tackling antisemitism.

“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,” he says.

Senior members of the Jewish community staged an unprecedented rally outside parliament in March, accusing Corbyn of failing to expel antisemites from the left of the Labour party.

A three-hour meeting of the NEC in July approved a controversial new code of conduct on antisemitism that omitted four examples from the IHRA definition, but the party also pledged to consult the Jewish community over the summer. Some Jewish leaders have declined to take part.

In his article, McCluskey also accuses the Labour MP Chuka Umunna of using the antisemitism row to justify his own rumoured plans to found a breakaway political party. The Streatham MP accused Labour of “institutional racism” in a recent column in the Independent, which many in Labour took as a signal that he is preparing to leave.

“Given the paucity of evidence that he actually produces to sustain his charge that he is a member of an ‘institutionally anti-Semitic’ party, it is fair to ask whether Umunna is merely exploiting the latest episode to justify his moves to breakaway from Labour,” he says.

In a series of tweets in response, Umunna said: “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.”