It follows a warning from the US president that America's trade deal with the UK "can always be changed".
Related stories
Golfer Jessica Bang, 18, dies while preparing for tournament in Thailand
‘Devastating’: bulldozers plough through Big Bend national park as Trump’s border work pushes ahead
Emergency alert warning of wildfire risk sent to phones in England and Wales
Trump asks US Supreme Court to allow $400m ballroom project to proceed
US forest service chief reportedly pressed staff for more support for wildfire near his ranch
Woman charged over vandalism of World War II Memorial in Washington, DC