“Eventually, physical demand growth for copper worldwide will come under pressure, as downstream players seek to defer consumption,” said Tom Price, commodities analyst at Panmure Liberum. The US imports about 60 per cent of its copper, primarily from Chile, with the rest met by domestic mines or recycled scrap.

Economists have long disliked tariffs and can point to research showing they harm the countries that impose them, including the workers and consumers in those economies.