James Roscoe, Britain’s second most senior diplomat in Washington, has abruptly left his post. The UK government gave no reason for his sudden departure, which comes amid an investigation into the leak of discussions at a meeting of the UK’s national security council.
A Foreign Office spokesperson confirmed: “James Roscoe has left his post.” Roscoe had served as deputy head of mission at the British embassy since 2022 and stood in as interim ambassador after the sacking of Peter Mandelson. He was among those tipped for the ambassadorial role, which ultimately went to Christian Turner.
Senior officials at the embassy are said to have been questioned as part of an investigation into reports of cabinet splits over allowing the US to use British bases for strikes against Iran. The leak is considered a serious breach of the Official Secrets Act. Justice Secretary David Lammy ordered the investigation after The Spectator reported that Prime Minister Keir Starmer suggested allowing the US to use bases for defensive strikes, facing opposition from several cabinet members.
As chargé d’affaires to the US, Roscoe played a key role in Donald Trump’s state visit to the UK in September 2025 and was involved in King Charles’s state visit to the US for the 250th anniversary of American independence. Before Washington, he served as UK ambassador to the UN and communications chief to Queen Elizabeth II from 2013 to 2016.
