The best British art of the 20th century is Jewish. It was the contribution of Jewish artists, many of whom were born in central Europe, that raised modern British art out of mediocrity and made it original. We will see this when the great Frank Auerbach has his Tate retrospective in the autumn. Ahead of that, an exhibition this summer offers a chance to reflect on what is distinctive about the Jewish voice in British art.

London’s Ben Uri Gallery is 100 years old and is celebrating its centenary with Out of Chaos, an exhibition that tells the story of Jewish émigré art in Britain since 1915. Not all of Britain’s outstanding Jewish art is the work of émigrés. Leon Kossoff was born in Islington – yet his parents had come to London from Russia.

As this exhibition demonstrates, all through the 20th century and into our own, Jewish migration brought new talent to Britain. Auerbach came here as a child saved from the Nazis – he is an orphan of the Holocaust. Lucian Freud too, came to Britain as a refugee from Germany, having spent his early childhood in Berlin.

Lucien Freud, pictured here in 1958, first came to London as a refugee from Germany. Photograph: Barrett/Hulton-Deutsch Collection/Corbis

One very obvious – and perhaps paradoxical – quality that Jewish artists injected into British art was the rawness and realism of central European modernism. Painters with a German heritage who had to flee Germany remained recognisably Germanic. Lucian Freud has a lot in common with the grotesque realism of the Weimar painter Otto Dix. Even more intriguingly, his erotic drive reflects the Vienna of his grandfather Sigmund, and the art of Egon Schiele.

Frank Auerbach paints with an expressionist intensity that is easy to trace back to German artists such as Ernst Ludwig Kirchner and the Austrian Oskar Kokoschka. Even though Auerbach and Freud both came to Britain as children, their adult styles have a much stronger affinity with German art than they do with, say, the Bloomsbury group.

The art historian EH Gombrich, who came to Britain from Vienna, rejected the idea that he should identify strongly as Jewish. In the Vienna of his youth, he pointed out, the only people who went about identifying “Jews” were antisemites. A look at Britain’s great Jewish painters proves this. There was no inherent difference between Jewish and German culture in early 20th century central Europe. The Nazis invented that distinction. Émigré Jewish artists did not bring with them a “Jewish” sensibility, but a German one.

That German modern sensibility is figurative, realistic, but also erotic, visceral and often with a dada rage. (It is no coincidence that one of Britain’s most important practitioners of dada, Gustav Metzger, fled Nuremberg as a refugee in 1939.) These daring figurative artists were able to appear to fit in with Britain’s staid, conservative appetite for portraits – while in fact having a radical sensibility that owed more to Der Sturm than the Royal Academy.

So why have Jewish artists made such a brilliant contribution to modern British culture?

Because they gave it a much-needed dose of German genius.