“If something can’t go on forever, it will stop.” This statement by Herbert Stein, chairman of the US council of economic advisers under Richard Nixon and Gerald Ford, tells us that debt cannot grow faster than an economy forever.

That is going to be true for China, too. What we do not know is when and how it will end. Will it be sooner or later? Will it be easy to cope with or will it be devastating? The manageability of China’s enormous domestic debts will be of great importance, not just for China, but for the many economies whose exports depend on it.

We cannot yet know how the debt surge will end. but we do know how it started. The trigger was the global financial crisis. Between early 2004 and late 2008, Chinese gross debt was stable at between 170 and 180 per cent of gross domestic product. This was higher than in other emerging countries, but not much higher. This seemed manageable.