Downing Street is thought to be aiming to keep the encounter relatively short to limit the chance of a disaster. As the talks are not in the Oval Office Mr Burnham should escape one of Mr Trump's unpredictable ad hoc press conferences. The president also has more high-profile showdowns scheduled with Xi Jinping of China and Volodymyr Zelensky.

The UN summit will bring together Donald Trump and Iran's president in New York while their countries are at war. The US president has signalled he's open for a meeting in a crucial week for international diplomacy.