LONDON — The British Foreign Office is used to tackling matters of import on a global scale.

This year, for example, it was involved when Britain expelled 23 Russian diplomats as retaliation after a former Russian spy was poisoned with a nerve agent on British soil.

It helped shepherd President Trump’s contentious visit to Britain in July and, later that summer, Prime Minister Theresa May’s trek to Nigeria, Kenya and South Africa — the first sub-Saharan trip to Africa by a British leader since 2013 — during which she riveted the world with her dance moves.