Boris Johnson’s search for a chief of staff to bring order to 10 Downing Street has proved so difficult that earlier this month civil war erupted in No. 10 after he offered the role to his longstanding director of communications Lee Cain. In the face of a backlash from figures including the Prime Minister’s partner Carrie Symonds and new press spokesperson Allegra Stratton, Cain ended up handing in his resignation — Dominic Cummings followed him out the door — and the search for a chief of staff continued.