It takes a lot to unite Britain's Jews, but Labour's stance on antisemitism has succeeded

Yesterday's Guardian newspaper features a letter signed jointly by the entire spectrum of British rabbis, 68 in all, from the strictest ultra-Orthodox to Liberal and Reform.

What is it that for the first time in Jewish history has united the Ultra Orthodox with the ultra liberal? What is it that has joined together the normally argumentative and quarrelsome Jewish community of the UK, which finds it difficult to agree on anything? What is it that has, in addition, caused one of parliament's most respected MPs, Chuka Umunna, to call his own Labour Pary 'institutionally racist'?

ReutersJeremy Corbyn's Labour Party is under fire for alleged antisemitism.

What has united them all is that the Labour Party has refused to listen to the Jewish community and is so widely ridden with antisemitism that it has, in the most insulting and arrogant way, chosen to redefine antisemitism in its own image and ignored the definition of what constitutes racism against us as a group, a religion and a people.

Throughout the ages, others have tried to tell 'the Jews' what to do, have tried to write us off, redefine us, ridicule us and often get rid of us. But for a political party which prides itself on its so-called 'socialist' values, its attractiveness 'to the many, not the few', Labour is not doing very well.

All this has come to a head during the historically most mournful period for the Jewish community. We are now in the 'Nine Days' before the Fast of Av, which takes place next Saturday night and Sunday – the most mournful day of the year, when Jewish people fast, afflict themselves and read the Book of Lamentations, seated on low stools.

For all that the Jews first came to this country in 1066 with William the Conqueror, if not before that in Roman times, and were then expelled around the Fast of Av in 1290 by King Edward, only to be readmitted again by Oliver Cromwell in 1656, there is not much to celebrate at present.

Jewish staff and students keep their heads down at universities, the educational establishment is threatening Jewish values in the school system, the State of Israel is constantly reviled in the media, and few seem to care.

However, when Labour, the main opposition party in the country which once was a hope and a haven to Jewish refugees and Holocaust survivors, uses populist and legalistic measures to redefine what Jew-hate is all about, flying in the face of what those of us who have experienced this hatred first-hand are telling the Party, then all hope must be deemed to be lost.

So the only solution, it seems to me, is to use the remainder of the nine days leading up to the Fast of Av to mourn the loss of the Jerusalem Temple on that date, as we normally do, together with the start of the First Crusade, the expulsion of the Jews from England, then from Spain, the First World War and some of the worst atrocities of the Second World War.

But we should now add to this terrible litany the loss of the Labour Party as we have known it. This Party has now morphed into something quite different.

In many ways this country is no longer the country it was, and nothing is impossible if decent people allow evil to flourish in their midst.

But the most tragic thing of all is that what has brought the entire Jewish community together – the most argumentative, disputatious, quarrelsome and often petty group of people on the planet – is the virulent antisemitism of the contemporary Labour Party led by Jeremy Corbyn and his cronies and the fact that they refuse to listen, ever.

Dr Irene Lancaster is a Jewish academic, author and translator who has established university courses on Jewish history, Jewish studies and the Hebrew Bible.