Trump hadn’t been in UK airspace for long when he called Labour’s London mayor, Sadiq Khan, a “stone cold loser”. Not unusual for a president who likes to verbally abuse his enemies, particularly given his long-running spat with Khan – but his bullishness, and the Conservative response, should still worry us.

In the same tweet the president called himself “by far the most important ally of the United Kingdom” and said that Khan had been “foolishly nasty” to him.