If something cannot go on forever, it will stop.” This is “Stein’s law”, after its inventor Herbert Stein, chairman of the Council of Economic Advisers under Richard Nixon. Rüdiger Dornbusch, a US-based German economist, added: “The crisis takes a much longer time coming than you think, and then it happens much faster than you would have thought.”

These quotations help us think about the macroeconomics of China’s economy. Growth at rates targeted by the government requires a rapid rise in the ratio of debt to gross domestic product. This cannot continue forever. So it will stop. Yet, since the Chinese government controls the financial system, it can continue for a long time. But the longer the ending is postponed, the greater the likelihood of a crisis, a big slowdown in growth, or both.

I have argued that it is in the interests of China and the rest of the world to keep their financial systems separate. The rapid growth of indebtedness and the size of its financial system represent a threat to global stability. China needs to rebalance its economy and stabilise its financial system before opening up capital flows. Western financiers will have a different view. We should ignore this sectional interest.