Morgan McSweeney, former chief of staff to UK Prime Minister Keir Starmer, has told MPs he made a "serious mistake" by recommending Lord Mandelson for the role of ambassador to the United States.
Testifying before the Foreign Affairs Committee, McSweeney said he had believed Mandelson's experience as an EU trade envoy would help secure a US trade deal. However, after new revelations about Mandelson's friendship with the late convicted sex offender Jeffrey Epstein emerged, McSweeney said it became clear the peer had not been fully truthful.
McSweeney admitted that Downing Street wanted Mandelson in post "quickly" but insisted officials were never asked to "skip steps" in the vetting process. He denied telling the Foreign Office that security checks "should be cleared at all costs."
Mandelson was granted security clearance despite concerns from vetting officials. Starmer has said neither he nor McSweeney knew the Foreign Office had overruled the vetting recommendation until recently.
Mandelson was sacked as ambassador in September 2025 after photos and emails revealing a closer relationship with Epstein came to light. McSweeney described seeing the revelations as "like a knife through my soul," adding that he had understood the relationship to be a "passing acquaintance" that Mandelson regretted.
A due diligence check before the appointment had flagged Mandelson's continued contact with Epstein after his conviction as a potential "reputational risk." McSweeney was asked by Starmer to send follow-up questions to Mandelson about Epstein, which he now believes were not answered truthfully.
Asked whether it was appropriate for him, as a friend of Mandelson, to pose those questions, McSweeney conceded it would have been "much better" for public appearances if the Cabinet Office's ethics team had handled it.
Earlier, former Foreign Office top civil servant Sir Philip Barton told the committee that Downing Street had been "uninterested" in the vetting process and focused solely on getting Mandelson in place before Donald Trump's inauguration. However, he denied that this pressure affected the substance of the vetting.
McSweeney acknowledged that the PM's office had chased the Foreign Office for updates but maintained no one asked to "skip steps" or was dismissive of national security.