An academics’ union has been sharply criticised by the Board of Deputies for distancing itself from a controversial new definition of anti-Semitism.

A motion put forward at the upcoming annual congress of the University and Colleges Union (UCU), which has 110,000 members, takes issue with the new International Holocaust Remembrance Alliance working definition, because it “conflates anti-Semitism with criticism of Israel”.

UCU, whose members include academics, lecturers and researchers working in education and prisons, will vote on the motion to dissociate itself with the IHRA definition and to “report all repressive uses of IHRA”.

The definition, backed by Theresa May in December, is not legally-binding and is meant to redefine anti-Semitism in 2017, covering those who mask their hatred of Jews with criticism of Israel.

However, leading lawyers said it had a “chilling effect” on free speech, particularly on Israel. Hugh Tomlinson QC called it “confusing” and said organisations using it were at risk of “unlawfully restricting legitimate expressions of political opinion”.

This week, however, Board of Deputies’ president Jonathan Arkush said the motion to disassociate the UCU from the IHRA definition was “deeply disappointing, not least because of similar motions in the UCU in the past,” in reference to the UCU’s past vote not to endorse the EUMC definition of anti-Semitism for similar reasons.

“Despite past form, it beggars belief that anyone in the UCU would want to dictate to Jews what constitutes anti-Semitic abuse against them,” he said. “This resolution seeks to deny victims of anti-Semitic abuse the right to call it out for what it is.”

UCU delegates were told that the definition has already been used “to intimidate academics who are engaged in activities that are critical of the policies of the Israeli government but that are not anti-Semitic”.

Earlier this year, Baroness Ruth Deech wrote to all university heads warning them about legal consequences of holding events such as those associated with Israel Apartheid Week.

Arkush added that the UCU motion was “disgraceful” and urged UCU delegates “to confront this pernicious affront to common decency, and stand with the victims of racist abuse, rather than the abusers”.

Elsewhere, UCU members “noted with dismay” that Professor Kamel Hawwash from the University of Birmingham, was prevented from entering Israel on 7 April on a trip with his wife and young son to visit relatives in East Jerusalem.

Palestinian-born Hawwash was banned because he supports the Boycott, Divestment and Sanctions (BDS) movement, and the UCU motion read: “BDS is a non-violent human rights movement… Israel’s action is an attack on basic freedom of speech as well as on the right to family life.”