You don’t think to tell the impressive fellow who has just asked you to the opera: “I’m worried about catching a falling piano.”

Only in the cultured world of private banking could the knock-on effects of the global financial crisis be expressed in these terms. But they do not refer to getting duff seats in the gods for Götterdämmerung, or a Laurel and Hardy-style mishap at a La Scala gala. Instead, they identify – albeit euphemistically – the structural flaws that have emerged in private banks’ business models.