The price of gold futures have soared to a record high after it was reported that the US would put tariffs on imports of 1kg bars in a further trade blow to Switzerland, which dominates the world’s refining industry.

Swiss exports to the US were hit by a crippling 39% tariff on Thursday after the country’s president returned empty-handed from a last-minute dash to Washington in an attempt to get the rate, among the highest imposed by Donald Trump, lowered.

It has subsequently emerged that US customs recommended that certain imports of gold bars that had been in a tariff exemption category should also be covered by the 39% rate.

The detail in a ruling letter – used by the US to clarify its trade policy – was signed on 31 July and seen by the Financial Times.