The world economy will not grow as it did during the boom, so how will it now expand? That is the cardinal problem in macroeconomics. The sources of demand that propelled the world into the boom have become sickly. The households and governments of the big deficit countries, such as the US and UK, are overstretched. They must take a break from their voracious consumption. So, if there is to be a sustainable recovery, who will step up to the cash register?

In Washington this week, a horde of 130 US Congressmen wrote to the Treasury with a demand: that it charge China with being a “currency manipulator” in its currencies report, due out in April, and that the US should retaliate by taxing Chinese imports.

Incendiary language, but a serious issue. The Chinese currency policy is, in effect, a development policy that works by subsidising foreign consumers who buy Chinese goods. The export machine, at its peak in 2008, was running a colossal $426bn current account surplus.