The UK learnt last week that its economy had shrunk by a real 1.5 per cent in the fourth quarter, the fastest rate of decline since 1980. Germany forecast an even sharper fall, while Singapore – an open economy and a bellwether for global trade – expects negative growth of as much as 5 per cent this year.

Across the world, standard measures of economic performance are suddenly producing terrible results. Maybe it is time to change them. Most experts agree that the commonly used indicator, gross domestic product, is an imperfect yardstick of economic activity. The trouble is, no one has yet invented a better one.