A single clause in Point 19 of the communiqué issued by the G20 leaders amounts to revolution in the global financial order.

"We have agreed to support a general SDR allocation which will inject $250bn (£170bn) into the world economy and increase global liquidity," it said. SDRs are Special Drawing Rights, a synthetic paper currency issued by the International Monetary Fund that has lain dormant for half a century.

In effect, the G20 leaders have activated the IMF's power to create money and begin global "quantitative easing". In doing so, they are putting a de facto world currency into play. It is outside the control of any sovereign body. Conspiracy theorists will love it.

There is now a world currency in waiting. In time, SDRs are likely evolve into a parking place for the foreign holdings of central banks, led by the People's Bank of China. Beijing's moves this week to offer $95bn in yuan currency swaps to developing economies show how fast China aims to break dollar dependence.

French President Nicolas Sarkozy said the summit had achieved more than he ever thought possible, and praised Gordon Brown for pursuing the collective interest as host rather than defending "Anglo-Saxon" interests. This has a double-edged ring, for it suggests that Mr Brown may have traded pockets of the British financial industry to satisfy Franco-German demands. The creation of a Financial Stability Board looks like the first step towards a global financial regulator. The devil is in the details.