“I will never apologise for changing an approach or strategy when the facts change,” said Hank Paulson when he abandoned plans to buy troubled assets. The US Treasury secretary sounds less flexible on the eve of his final trip to Beijing: he is calling again on China to strengthen the currency.

Depending on where you sit, Beijing could be said to have done just that. The renminbi has gained around one third against the South Korean won since early July. On a trade-weighted basis it is up more than 10 per cent. The perspective from Washington is different. After a rise of 20 per cent against the dollar following revaluation in 2005, appreciation has come to a standstill since this summer. Worse, the renminbi actually fell a hefty 0.9 per cent against the dollar on Monday, and dipped again on Tuesday. The non-deliverable forwards market is pricing in more depreciation, although this is an imperfect indicator.