They will not have all the answers for what a post-credit crunch world should look like. But when the world’s leading economies meet in Washington on Saturday to discuss the global financial crisis – albeit without Barack Obama, US president-elect – they should at least be able to put in place the basics of an immediate rescue plan.

The Group of 20 summit marks a break with a practice that has outlived its usefulnesss. The notion that a club of just eight rich democracies could run the world in normal times, let alone through the current turmoil, was always implausible. It would be pointless even trying without Brazil, China and India. Only by including these countries will it be possible to find a way out of the current crisis and agree longer-term reforms of the global financial architecture.