And in the economy behind the Great Wall, exports crashed last month. Well, not exactly a crash; in a sense, the fall was quite modest. But in China, rapid growth has become so normal, that any fall feels like a crash. Imports fell too, and this time it really was a bona fide crash. That has another set of disturbing implications.

In all, Chinese exports fell by 2.8 per cent in December, close to the biggest monthly drop in ten years. Frankly, given the state of China’s export market this is hardly surprising. In fact, economists had expected a bigger fall.

Unemployment in urban areas is rocketing. Protests are growing. China is being forced to grapple with the reality that if growth falls below a level any other country would be delighted with, unemployment rises, and social unrest becomes dangerous.

The remedy has long been clear. China was too reliant on export driven growth, consumption badly needs to rise.

The snag is, consumption is in the mire too. Not only did exports fall last month, so too did imports. In fact, imports were down 21.3 per cent.

As for the Chinese trade surplus, it soared, hitting $39bn. China has only ever enjoyed a higher surplus than that once.

So if the real problem with the global economy is imbalances, then the latest news from China just seems to suggest the imbalances are growing.

There is a real crisis in the making here. In the US, the pressure is on Barack Obama to do whatever he can to persuade the Chinese to allow the yuan to appreciate. The dangers of a trade war grow – and that is the last thing we need right now.

Ultimately, the way this economic crisis pans out depends on trade. More trade, and the global economy will recover. Step back to protectionism, and it is difficult to see how things can go anywhere but down.