The central bank helicopters are planning a co-ordinated drop of liquidity on troubled market waters. The money to be dropped now is not that large. But if this does not work, more will surely follow. The helicopters will fly again and again and again.

One point is clear: central banks must be pretty worried to take such a joint action. For what is remarkable about yesterday's statement is that five central banks - the Bank of Canada, the Bank of England, the European Central Bank, the Federal Reserve and the Swiss National Bank - are co-ordinating their (different) interventions. Their hope must be that this action will trigger not panic ("What do the central banks know that I do not?") but confidence ("Now that the central banks are prepared to intervene in this way, I can at last stop worrying").