So this is what happens when accepted rules of global behaviour are abandoned. The sense of complacency in the world’s sharemarkets can suddenly be replaced by near-panic. The fallout from a US-China trade war that looks like turning into a global currency war means any potential exit looks more like a dead end.

Market sentiment turns more rapidly than political sentiment. When Donald Trump decided to use the imposition of more tariffs to break an uneasy truce with China on trade, it produced a rapid escalation of hostilities. Apprehension about the impact is unlikely to be contained even if the mood improved after China pulled back on Tuesday from allowing any further decline in its currency.