Now the illusions have worn off and the search is on for a target that the Bank can hit. Perhaps this one can be tweaked — or perhaps everything will be all right when Mark Carney, the new governor from Canada, takes over in July. Even so, Charles Goodhart may take some persuading. He is the sage who laid down, a generation ago, that if you hitch policy to a single indicator, it will cease to tell you the truth. Goodhart’s Law has been borne out by events.

Alan Greenspan at the US Federal Reserve once suggested another approach to inflation. People, he said, should not need to take it into account in making their decisions. That ambition proved elusive, but at least he did not claim that it was an if-only.