The European Union is facing a higher 15% tariff rate on its goods imported to the U.S. compared to the 10% levy the U.K. has agreed to. "In theory, the UK benefits," Philip Shaw, chief economist at Investec, told CNBC.

European Commission President Ursula von der Leyen headed to Scotland on Saturday ahead of a meeting with U.S. President Donald Trump on Sunday afternoon, Commission spokespeople said, as officials from both sides said they were nearing a trade agreement.