This summer has confirmed what many of us already feared: a global recovery which appeared to be taking hold 12 months ago has now stalled. Three years after the financial crisis erupted, the world faces the triple challenge of growth, debt and bank instability. Each is difficult enough to overcome: together they make a poisonous cocktail.

Last week’s Jackson Hole conference made it painfully clear that these challenges can be tackled only with greater international co-ordination. It revealed a lack of agreement on fundamental questions between the International Monetary Fund, European Central Bank and US Federal Reserve, while exposing the absurdity of discussing these issues only at an academic conference of central bank governors, rather than a meeting of our political leaders. We cannot go on like this. The international community must start speaking with one voice – and fast.

The risks to market confidence and plummeting prospects for global growth mean we cannot risk waiting until November’s meeting of leaders of the Group of 20 leading economies. It should be brought forward and I hope David Cameron will make this case when he sees Nicolas Sarkozy, the G20 chairman, at today’s meeting on Libya.