If you are a liberal, as Londoners should be — this is the second most multicultural city on earth — you can hold two ideas in your head at once. The first is that the so-called “pro-Palestine” marches in London — I doubt their “pro” nature, as some seem keener for a war on Israel than a settlement for Palestine — contain antisemitic elements. The second is that they should go ahead anyway. If you live in a pluralistic democracy, you must learn to fight without rancour, or you won’t live in a pluralistic democracy that long.