A decade ago, as the global financial crisis gripped one economy after another, the need for co-ordinating policy became acute. Central bankers, as is often the case, were the first to move, agreeing an orchestrated interest rate cut in October 2008 and establishing dollar swap lines to keep liquidity flowing into markets.

But even governments, traditionally slower to act together, were stung into action. The G20 grouping of large economies, founded in 1999 as a response to the Asian financial crisis, had largely languished as a serious policymaking forum. It served as a talking shop for officials, often at junior levels, but took essentially no binding decisions.

Instead, the G7 of rich countries — temporarily expanded to the G8 with the inclusion and then expulsion of Russia — attempted to serve as the steering group for the world economy. But there was always a sense, particularly as China and other fast-growing emerging market countries took a bigger share of the world economy, that real legitimacy was missing.