Officials in the US must be jealous. Recent events suggest China's monetary authorities have more credibility than the Federal Reserve. Attempts to talk up the US dollar have been unsuccessful because the markets do not believe interest rates will be raised in the face of a troubling economic outlook. China's monetary policy is similarly constrained, albeit because of the perception of exchange rate undervaluation rather than weak growth. But Beijing has been extremely successful in promoting the idea that policy is tight.

To confirm this, ask ordinary people, speak to global investors or scan media reports. And, of course, "tight" is a condition clearly understood and usually not welcomed by the asset markets. The big sell-off in the Chinese stock market, the start of which can be timed almost exactly to the shift in government rhetoric at the end of last year, suggests as much.