The international monetary system needs fundamental reform. It is not the cause of the recent imbalances and current instability in the global economy, but it certainly has been ineffective in addressing them. So a broad set of reforms is required, beginning with an immediate expansion of the current system of Special Drawing Rights (SDR), or money that can be issued by the International Monetary Fund. And here the Group of 20 leading nations must take the lead.

John Maynard Keynes once proposed a global currency, the Bancor, to be placed at the centre of the international monetary system. The idea never caught on. Instead we now have a system dominated by holdings of US dollars. This has several disadvantages. The first is it creates a global recessionary bias during and after financial crises – because it places the burden of adjusting to payments imbalances on nations which run a deficit.

The second is the tension it creates, due to the use of a national currency, the dollar, as the global currency. This can lead to global volatility as a result of growing US current account deficits. These deficits are necessary, for creating sufficient global liquidity, but they also generate excessive indebtedness, both external and internal. So if the US were to shrink its deficit too quickly, a deficiency of supply of the global reserve currency could result.