Since the Bretton Woods system of fixed exchange rates collapsed in 1971, some of the most high-profile attempts at global co-ordination have involved trying to stabilise major currencies. But the mixed record of these ad hoc efforts gives reluctant countries such as China an excuse not to repeat them – suggesting that, for now, the Group of 20 leading nations will struggle to even try to match the role played by its predecessors, the G5 and G7.

After the collapse of Bretton Woods, some European countries attempted to manage their exchange rates against each other in the evocatively named “currency snake”, which hardened into a more formal system of fixed values and, eventually, the euro.

Otherwise, however, currencies swung against each other, sometimes wildly, as the economic and monetary turmoil of the 1970s combined with high and volatile oil prices to push exchange rates around.