The sheer irrationality in which anti-Semitic beliefs are anchored can sometimes feel contagious. When a BBC London presenter called me ‘Hezbollah’ live on air for a full 40 minutes, I thought of that scene in Annie Hall, when Woody Allen’s Alvy recounts lunching with a telly exec whose ‘Did you?’ he hears first as ‘didchoo’ and then as ‘Jew’. London, mercifully, is not Hungary or France or Sweden, all places in which it’s becoming increasingly dicey to identify as Jewish. Nevertheless, as Jews, Gentiles and everything in between, we would do wrong to overlook those milder instances of anti-Semitism. Though they seem to occasion nothing more than fleeting social discomfort, they create an atmosphere of altogether less benign tolerance — the kind of tolerance that results in that wedding video or those football chants or intimations of ethnic fifth columnism. The kind of tolerance, in short, that betrays the London that ultimately told Oswald Mosley’s Blackshirts to get lost.