More than 30 years ago, Denis Healey, a UK Labour chancellor of the exchequer, said he wanted to be to economic forecasters what the Boston Strangler was to door-to-door salesmen. Unfortunately, he did not succeed.

Indeed, I have had an uneasy foreboding since the mainline economic forecasts at the beginning of 2007 evinced a remarkably favourable prospect. As recently as this summer, the editorial in the June Organisation for Economic Co-operation and Development Economic Outlook said: “The current economic situation is in many ways better than what we have experienced in years”. I single out this forecast because it was one of the clearest and best-reasoned ones. The authors were well aware of the risks, and even had a “box” on subprime mortgage markets. Nevertheless, they decided to stick with their projections. Similar optimism was exhibited by the main official national forecasts.