In the seven years since it was elevated to the level of supposed guardian of global stability, the G20 grouping of large economies has struggled to make a noticeable impact.

In general, though they have paid lip service to global co-operation over macroeconomic policy, none of its members has been overly bothered about ignoring the views of the rest of the group. Each has generally gone its own way on fiscal, monetary and exchange rate policies.

But at Friday’s meeting of G20 finance ministers in Shanghai, the stakes for failing to co-ordinate policy across the world are higher than for some time. With recent financial market turmoil and great uncertainty about Chinese economic prospects, a sense of unease has persisted since the turn of the year.