When they met in Washington last November they were still in a state of shock at the wreckage that was the private banking system. Meeting again five months later in London they were faced with an ever deepening global recession and the real risk of global contagion.

This week, when the leaders of the Group of 20 leading economies gather in Pittsburgh for their third meeting within a year, the world economy is once again growing, equity markets have recovered most of their losses and talk of a coming depression has disappeared. Participants would be excused for feeling they have been through the mill.

Sentiment and economic numbers have improved but policymakers are far from euphoric, chastened by the experience of the past year and the desire to prevent any repetition. They also know that a surprisingly sunny economic spring does not guarantee a sizzling summer, let alone an agree-able climate in future years to come.