The open secret about London’s cherished “special relationship” with Washington is that it is a great deal more special for the British than for the Americans.

Winston Churchill embellished the relationship with all manner of flummery, including shared ideals and values, a common language and unique bonds of kith and kin. US presidents have taken an unsentimental view, always measuring the bargain against the national interest.

As far back as the 1960s, an adviser to John F Kennedy’s White House pointed up the asymmetry. Whatever the view in London, Richard Neustadt observed, Washington saw the UK as “a middle power, neither equal nor vassal, which history, geography or economics rendered especially significant to us for the time being”. For London, the relationship was existential. In Washington it was a nice to have.