US President-elect Donald Trump's America-first principle is likely to dominate Washington's approach to international relations, leading to a "complicated" road ahead for traditional ally Britain, with issues like trade, Ukraine and European defence in the spotlight, says an analyst. "There are going to be lots of complicated moments," says director of the thinktank Chatham House Bronwen Maddox. "Really it comes down to the America-first principle that Trump is very obviously following, and that means no favours on trade and probably a division of opinion on Ukraine, on how to underpin Europe's security, and potentially on the Middle East." SOUNDBITES