Dame Emily Thornberry, chair of the Commons foreign affairs committee, has written to Foreign Secretary Yvette Cooper seeking detailed answers about the vetting process that preceded Lord Mandelson’s appointment as Britain’s ambassador to the United States and his subsequent dismissal.
In a letter sent after Ms Cooper took office, Dame Emily said she had “repeatedly” sought to question Lord Mandelson before his departure for Washington in February but was denied by the Foreign Office and by Ms Cooper’s predecessor, David Lammy. She asked what security concerns were raised during the vetting process, how the Foreign Office responded to those concerns and whether any conditions were imposed on Lord Mandelson’s remit.
Dame Emily wrote that it had been suggested security concerns may have been overlooked and that decisions on the appointment “may have been taken by actors outside of the Foreign Office, perhaps senior people in No 10.” She described those allegations as “potentially very serious” and said it was her responsibility to ensure the House of Commons received “a thorough response to a number of important unanswered questions.”
Lord Mandelson was appointed by Prime Minister Sir Keir Starmer as Britain’s ambassador to the United States but was sacked after the scale of his links to Jeffrey Epstein emerged. The dismissal followed the publication of emails showing Lord Mandelson had sent supportive messages to Epstein while Epstein faced jail for sex offences. Photographs published in May 2025 showed Lord Mandelson with former US President Donald Trump in the Oval Office during a meeting in Washington.
A No 10 spokesman said on Friday that the prime minister had confidence in the vetting system. “We always keep national security vetting and other procedures under constant review to make sure they retain their position as world-leading,” the spokesman added.
Dame Emily’s letter seeks clarification on whether the Foreign Office considered any of the concerns a “potential barrier” to appointment and whether any restrictions were placed on Lord Mandelson’s duties in light of those concerns. She also called on the department to review pre-appointment scrutiny to prevent “embarrassing diplomatic incidents” in future.
The request for answers comes amid wider political scrutiny of ministerial appointments and the intersection of political influence and security vetting. Ms Cooper has been in the foreign secretary role for about a week, and Dame Emily’s intervention signals unrest within Labour’s ranks over how the matter was handled.
Downing Street and the Foreign Office have declined to provide further detail about what specific concerns arose during vetting, citing the sensitive nature of security processes. Parliamentary committees routinely seek assurances about appointment procedures, and Dame Emily’s committee has the remit to examine whether proper safeguards were applied in this case.
Labour leadership figures, including Sir Keir, initially defended Lord Mandelson following his appointment. That support shifted after the publication of the emails that prompted fresh scrutiny and ultimately led to his removal.
Dame Emily asked Ms Cooper to provide a full account of the pre-appointment advice and the communications between the Foreign Office and No 10 that related to Lord Mandelson’s selection and clearance. She said transparency about those exchanges was necessary to restore confidence in the process.
The Foreign Office said it would respond to parliamentary scrutiny in due course. Ms Cooper’s office did not immediately comment on the substance of Dame Emily’s letter beyond acknowledging receipt and noting the department takes vetting and security matters seriously.