Kim Darroch quits as UK ambassador to US 'after Johnson remarks'

Sir Kim Darroch, the UK ambassador to Washington who has been at the centre of a diplomatic row over leaked cables criticising Donald Trump, has resigned.

The Guardian understands he concluded his position was untenable after watching the Conservative leadership debate on Tuesday, in which the frontrunner, Boris Johnson, stopped short of backing him.

In a letter to Simon McDonald, the most senior official at the Foreign Office, Darroch said the row, in which Trump called the ambassador “a pompous fool” and “very stupid”, meant he could not continue.

Kim...