Mark Sedwill, the most senior official in Boris Johnson’s government, will stand down in September, Downing Street confirmed.
Sedwill will leave his posts as Cabinet secretary, head of the U.K. civil service and national security adviser.
His departure comes after months of speculation about his position, amid reports that he has clashed with Johnson’s Downing Street team. It was announced 24 hours after Cabinet Office Minister Michael Gove gave a speech setting out the government’s plans for major reforms of the civil service, while criticizing many aspects of the way Whitehall operates.
The U.K.’s chief Brexit negotiator and close Johnson ally, David Frost, will take over as national security adviser and the government will shortly launch the search for Sedwill’s successor as cabinet secretary and head of the civil service.
Sedwill was appointed as Cabinet secretary — Whitehall’s top job — by Theresa May in October 2018, succeeding Jeremy Heywood, who had been diagnosed with lung cancer, and died in November 2018. Sedwill has held the national security adviser position since April 2017 and before that was the top official at the Home Office under May.
Sedwill will take on a new role leading a “G7 panel on global economic security,” Downing Street said, as the U.K. takes on the presidency of the international group next year.
In his resignation letter to the prime minister, Sedwill said: “Two years ago, when my predecessor fell ill, your predecessor asked me to step in as Cabinet secretary, and you asked me to continue to support you through Brexit and the election period. It was obviously right to stay on for the acute phase of the COVID-19 crisis. As you are setting out this week, the government’s focus is now shifting to domestic and global recovery and renewal.”
Sedwill thanked Johnson for his “confidence and friendship as both foreign secretary and prime minister.”
Johnson is expected to give a speech on Tuesday setting out the government’s plans for the coronavirus recovery. In his reply to Sedwill, the prime minister said: “Over the last few years I have had direct experience of the outstanding service that you have given to the government and to the country as a whole.
“It has been by any standards a massive contribution — but as PM I have particularly appreciated your calm and shrewd advice.”
Welcoming Frost to his new role in a separate statement, Johnson said: “I have asked David to help me deliver this government’s vision for Britain’s place in the world and to support me in reinvigorating our national security architecture and ensuring that we deliver for the British people on the international stage.”
Frost said he would stay on as chief Brexit negotiator until the end of talks on the future relationship between the U.K. and the EU. The post-Brexit transition period is due to end on December 31, by which time the U.K. hopes to have negotiated a free-trade agreement with the EU.