Downing Street will in the coming weeks announce a replacement for Sir Mark Sedwill as Cabinet Secretary. It is the most powerful job in Whitehall, with the newcomer expected to oversee the response to coronavirus and to overhaul the Civil Service machine. Yet we know very little about how the appointment is made.

Previous prime ministers have personalised the selection process to fit their individual needs: “It doesn’t happen that often, because cabinet secretaries stay on for a long time,” said Peter Ricketts, a former National Security Adviser. “It’s always someone the PM personally favours, someone they want to trust.”