We live in an age of demonstrations – but the one protest you never see is a Jewish one. Until this week, when it was revealed that the leader of the British Labour Party had posted approvingly about a Protocols-of-Zion style public mural. This triggered the first public protest against anti-Semitism since 2012. But taking to the streets is a huge departure for the Jewish community, whose security has typically rested on fitting in. Unlike other minority groups – which now self-organise at the smallest provocation – Jewish organisations try to keep calm and carry on. This was the thrust of last year’s major report into anti-Semitism by the Institute for Jewish Policy Research (IJPR), in spite of it being commissioned in response to a 30 percent rise in anti-Semitic incidents. Sitting behind this enforced calm is the memory that Jewish de-assimilation can be fast and fatal. Berlin and Vienna were both thriving Jewish centres right up to the First World War, in which German-speaking Jews served with distinction. What came next was too fast …