UK Prime Minister's Chief of Staff Resigns Amid Mandelson Appointment Controversy

British Prime Minister Keir Starmer's chief of staff, Morgan McSweeney, resigned on Sunday, acknowledging his role in the contentious appointment of Peter Mandelson as the U.K. ambassador to the United States. McSweeney stated, "The decision to appoint Peter Mandelson was wrong. He has damaged our party, our country and trust in politics itself. When asked, I advised the Prime Minister to make that appointment and I take full responsibility for that advice."

Mandelson, a former Cabinet minister, was appointed ambassador in 2024. However, recent disclosures revealed his continued association with convicted sex offender Jeffrey Epstein after Epstein's 2008 conviction. Documents suggest that Mandelson shared sensitive government information with Epstein during the 2008 financial crisis.

In response to these revelations, Prime Minister Starmer dismissed Mandelson from his ambassadorial role in September 2025. Starmer apologized for "having believed Mandelson's lies" and acknowledged that the depth of Mandelson's relationship with Epstein was not fully understood at the time of his appointment.

McSweeney's resignation follows mounting pressure within the Labour Party and public criticism over the appointment. His departure is seen as a significant blow to Starmer's administration, given McSweeney's pivotal role in the party's recent electoral success.

The controversy has intensified scrutiny of the government's vetting processes for high-level appointments. McSweeney emphasized the need for a fundamental overhaul of these procedures to prevent similar issues in the future.

As the Labour Party navigates this crisis, questions remain about the potential impact on Starmer's leadership and the party's standing with the public.