At last, one piece of good news from the financial crisis: oil prices have collapsed. In July, crude oil for New York delivery traded at more than $146 a barrel. Three months on, it has almost halved to $74. Some believe it could fall further. The same analysts at Goldman Sachs who first predicted crude could rise above $100 now believe it could drop as low as $50.

This is an unexpected boon. Lower oil prices mean lower inflation, which leaves greater scope for central banks to lower interest rates, too.