The order raises import taxes for US-based firms buying from other countries from today - but the levy remains at 25% for the UK.

U.S. President Donald Trump's 50% tariffs on most imported steel and aluminum went into effect on Wednesday, an increase from previous 25% rate that had been in place.

The president has ratcheted up the rate on foreign metals to 50 percent, double the previous rate, saying the levies weren’t high enough to help the U.S. industry.