For all its talk, China bought a further $25bn of US Treasuries in June and $25bn in July. The weak yuan has helped to keep China's factories open – and to preserve social order – during the economic crisis, though exports were still down 23pc in August. But this policy is on borrowed time. Reformers in Beijing are already orchestrating a profound shift in China's economy from export reliance (38pc of GDP) to domestic demand, and they know that keeping the dollar peg too long will ultimately cause them to lose export edge anyway – via the more damaging route of inflation.