Perhaps the most disturbing element is not merely that China's economy appears so vulnerable to a slackening in demand for exports, but that such growth started weakening even before a particularly severe global slowdown was in train.

Nicholas Lardy, a China expert at the Peterson Institute for International Economics in Washington, says that the rough arithmetic of China adding a percentage point to global economic expansion each year – growth of 10 per cent in an economy that makes up about a tenth of world gross domestic product – will no longer hold. “China's contribution to global growth is declining rapidly,” he says.

China's net exports have contributed 2.3 percentage points or 2.4 percentage points of growth to the Chinese economy over the past few years. “That has halved even in advance of a major global slowdown in the first three quarters [of 2008], and is likely to drop further,” Mr Lardy says. Chinese net trade – exports minus imports – improved in the most recent months but that mainly reflects a fall in the price of imported oil and, adjusted for prices, its contribution to China's growth has been falling.