Steven Mnuchin, the US Treasury secretary, says that if countries ‘arbitrarily tax our digital companies’ retaliatory taxes on car companies will be looked at

Boris Johnson is planning to push ahead with plans for a tax on large technology companies despite the threat of a trade war with the US.

Downing Street said it will introduce a 2 per cent sales duty on companies such as Facebook and Google from April despite the threat of retaliatory tariffs.

Steven Mnuchin, the US Treasury secretary, made clear at the World Economic Forum in Davos that President Trump intended to hit back if countries press ahead with digital taxes.

“If people want arbitrarily to put taxes on our digital companies, we’ll consider arbitrarily putting taxes on car companies,” said Mr Mnuchin.

Downing Street said that imposing tariffs “would harm businesses and consumers on both sides of the Atlantic”.

The automotive industry is