Britain's most senior civil servant stepped down on Sunday after reports of clashes with Prime Minister Boris Johnson's top political adviser, part of what is expected to be a wider shake up of officials at the heart of power.
Johnson's senior political adviser, Dominic Cummings, has long been critical of the civil service, saying government is not nimble enough to deliver change. Some newspapers reported he warned aides last week that a "hard rain is going to fall".
Earlier this year, Johnson forced the resignation of his finance minister, tightening his control over the treasury, and just earlier this month he announced the merger of its diplomatic and aid departments.
Mark Sedwill, a career diplomat, was appointed cabinet secretary and national security adviser by Johnson's predecessor Theresa May. In a letter to Johnson released on Sunday, he wrote that, having stayed on for "the acute phase" of the coronavirus crisis, he was now leaving as "the government's focus is now shifting to domestic and global recovery and renewal".
Johnson's office released a letter in which he thanked Sedwill for his "outstanding service", and asked him to lead a new G7 panel on global economic security as Britain assumes the presidency of the rich nations' group.
David Frost, Britain's chief negotiator with the European Union, will replace Sedwill as national security adviser and there will be a competition to appoint a new cabinet secretary and head of the civil service.
