Donald Trump hit dozens of US trading partners with tariffs while formalising recent deals with others including the UK and EU, as he plunged the global economy into a new era of mercantile competition.

Crucial exporters to the US such as Taiwan, the world’s most important semiconductor exporter, will incur steep new levies. Trump also raised tariffs on Canada, an ally and major trading partner, to 35 per cent. India was hit with a rate of 25 per cent and Switzerland with 39 per cent.

The US president’s executive order on Thursday evening announcing the tariffs said they were designed to lower America’s trade deficit with many countries, which it described as an “unusual and extraordinary threat to the national security and economy of the United States”.