Sir Matthew John Rycroft (; born 16 June 1968) is a British civil servant and diplomat serving as Permanent Under-Secretary of State at the Home Office since 2020, appointed following the resignation of Sir Philip Rutnam. Rycroft previously served as Permanent Secretary at the Department for International Development (DFID) from 2018 to 2020 and as the Permanent Representative to the United Nations in New York from 2015 to 2018. Early life and education Rycroft was born in Southampton, before moving to Cambridge at the age of eleven. He studied mathematics and philosophy at Merton College, Oxford. Career Rycroft joined the Foreign and Commonwealth Office (FCO) after graduation, in 1989. Following short spells in Geneva and on the NATO desk in Whitehall, Rycroft spent four years at the British embassy in Paris. In 1995–96, Rycroft was Head of Section in the Eastern Adriatic Unit at the FCO: a demanding role, given the aftermath of the Yugoslav Wars. Very soon after taking up this role, he served as a member of the British deputation to the Dayton peace talks. Between 1996 and 1998 he was a desk officer in the FCO Policy Planners. In 1998, he joined the British embassy in the United States, where he served for four years. In 2002, Rycroft was appointed Private Secretary to Prime Minister Tony Blair, to advise him on matters related to foreign policy, the European Union, Northern Ireland and defence. During this time Rycroft wrote a letter to Mark Sedwill, private secretary to the foreign secretary, Jack Straw. The letter reveals that "we and the US would take action" without a new resolution by the UN security council if UN weapons inspectors showed Saddam had clearly breached an earlier resolution. In that case, he "would not have a second chance". That was the only way Britain could persuade the Bush administration to agree to a role for the UN and continuing work by UN weapons inspectors, the letter says. Dated 17 October 2002. "This letter is sensitive," Rycroft underlined. "It must be seen only by those with a real need to know its contents, and must not be copied further." It was in this capacity that Rycroft issued the "Downing Street memo". During his time in Downing Street, in 2003, he was made a CBE. From March 2005 to July 2008, Rycroft served as Ambassador to Bosnia and Herzegovina. In July 2008, he was