The UK delegation of the International Holocaust Remembrance Alliance (IHRA) has issued a damning rebuke to Labour, warning that rejecting its definition of Jew-hate would undermine it and help bring about "a world where antisemitism goes unaddressed".
A statement signed by seven members – including Sir Ben Helfgott and the Holocaust Education Trust chief executive’s Karen Pollock – says the definition was “drafted with input from some of the world’s foremost experts on antisemitism” and “unanimously approved” by government representatives from 31 countries.
Labour has tried to claim its own code of conduct on antisemitism - which omits key example relating to criticism of Israel and has caused a huge standoff with its Jewish MPs and supporters - is more robust.
But in a clear criticism of the party, the IHRA statement says: "Any ‘modified’ version of the IHRA definition that does not include all of its 11 examples is no longer the IHRA definition...
"If one organisation or institution can amend the wording to suit its own needs, then logically anyone else could do the same.
“We would once again revert to a world where antisemitism goes unaddressed simply because different entities cannot agree on what it is.”
Other signatories include Dr Gilly Carr of Cambridge University, Dr Paula Cowan, from the University of West Scotland, Olivia Marks-Woldman of the Holocaust Memorial Day Trust and Alex Maws of HET and Michael Newman from the Association of Jewish Refugees (AJR).
The statement adds: "The significance of this definition lies in the international cooperation that led to it.
"Not only was it drafted with input from many of the world’s foremost experts on antisemitism, but it was unanimously approved by government representatives from all IHRA Member Countries. Gaining this level of international consensus was no easy feat, but antisemitism is a global phenomenon and so it was very important that we persevered in order to emerge with one common definition.
"As a result of this IHRA effort, there is not a western or an eastern definition of antisemitism; there is not a Jewish or non-Jewish definition – but an international definition.
"Any ‘modified’ version of the IHRA definition that does not include all of its 11 examples is no longer the IHRA definition.
"Adding or removing language undermines the months of international diplomacy and academic rigour that enabled this definition to exist. If one organisation or institution can amend the wording to suit its own needs, then logically anyone else could do the same.
" We would once again revert to a world where antisemitism goes unaddressed simply because different entities cannot agree on what it is.
"The real everyday threats to Jewish people and their communities demand coordinated international solutions.
"As members of the UK delegation to the IHRA, we are pleased that our work has provided an important tool to unite policymakers and stakeholders of different nationalities and ideologies in this urgent fight."
The statement was released on Tuesday as Labour MPs demanded a vote in the House of Commons to force Jeremy Corbyn to accept the IHRA definition of journalism when parliament returns from recess.
They believe a non-binding vote would force him to back the definition in Parliament and later adopt it in full for the party.
Labour’s Chris Leslie, who has the backing of the Board of Deputies, other political leaders and a group of prominent MPs, has asked Leader of the Commons Andrea Leadsom to allocate time for a debate so politicians can show their support to the Jewish community.
In a letter to Ms Leadsom, Mr Leslie called for Parliament to adopt the definition and "send the clearest of signals that antisemitism of any kind will not be tolerated".
He wrote: "You will be aware of the distress caused to many of our Jewish constituents at the rise in antisemitism and the debate about the appropriate definition of antisemitism.
"Like the vast majority of MPs from across the political parties I believe that the IHRA have provided the correct framework for identifying anti-Semitism in their working definition and accompanying examples."