James Roscoe, Britain's second most senior diplomat in Washington, who served as interim ambassador after Peter Mandelson's dismissal, has abruptly left his post. The UK government provided no reason for his sudden departure, which comes amid an investigation into the leak of discussions from a National Security Council meeting.
A Foreign Office spokesperson stated: "James Roscoe has left his post," offering no further explanation. Roscoe had been deputy head of mission at the British embassy since 2022.
Roscoe was among candidates considered for the ambassadorial role following Mandelson's removal due to his ties to convicted sex offender Jeffrey Epstein. The position ultimately went to career diplomat Christian Turner.
Senior embassy officials are said to have been questioned as part of an investigation after reports this year revealed cabinet divisions over allowing the US to use British bases for strikes against Iran. Such discussions are protected by the Official Secrets Act, and leaks from the National Security Council are considered serious breaches. In 2019, then-Prime Minister Theresa May sacked Defence Secretary Gavin Williamson over a leak.
Justice Secretary David Lammy ordered an investigation into the apparent leak. The Spectator reported that Prime Minister Keir Starmer proposed allowing the US to use British bases for defensive strikes against Iranian targets at a meeting last Friday, facing opposition from Ed Miliband, Rachel Reeves, Yvette Cooper, and Shabana Mahmood. The report was subsequently picked up by multiple media outlets.
As chargé d'affaires to the US, Roscoe played a key role in Donald Trump's state visit to the UK in September 2025. More recently, as second in charge at the embassy, he was involved in the King's state visit to the US marking the 250th anniversary of American independence.
Before moving to Washington, Roscoe served as UK ambassador to the UN and was communications chief to the late Queen Elizabeth II from 2013 to 2016. He also served as chief press officer in Downing Street for Prime Ministers Tony Blair and Gordon Brown. His earlier diplomatic postings included the UN, Sierra Leone, and Iraq.
Roscoe reportedly viewed his role as operationally focused on "cleaning up the mess" in smoothing relations with the White House, rather than acting as a figurehead of UK relations.
