Morgan McSweeney has resigned as Prime Minister Keir Starmer’s chief of staff, deepening a political crisis over the appointment of Lord Peter Mandelson as Britain’s ambassador to the United States.
The departure follows mounting pressure over McSweeney’s role in advising Starmer to make the appointment despite Mandelson’s publicly known past links to convicted sex offender Jeffrey Epstein.
The controversy has continued to widen as new disclosures, internal party anger, and a police investigation have converged around the decision.
The resignation leaves Starmer facing renewed questions about judgment and leadership less than two years into his premiership.
McSweeney said he took responsibility for advising the prime minister to appoint Mandelson, while stressing he did not oversee the vetting process.
In a statement, he said, “The decision to appoint Peter Mandelson was wrong. He has damaged our party, our country and trust in politics itself.”
Labour lawmakers have grown increasingly vocal, with several calling for Starmer to step down as party leader.
The crisis has been fueled by the release of U.S. court files detailing the extent of Mandelson’s continued contact with Epstein after his 2008 conviction.
Those revelations followed Starmer’s decision in September to sack Mandelson from the ambassadorial role after earlier emails showed supportive messages sent to Epstein.
Opposition leaders seized on McSweeney’s resignation, arguing it underscored broader failures at the top of government.
British police have opened an investigation into alleged misconduct in public office after emails suggested Mandelson may have shared sensitive information with Epstein while serving as a minister.
The government has since agreed to release nearly all previously private communications related to Mandelson’s appointment, a move expected to bring further scrutiny.
Starmer has said Mandelson’s relationship with Epstein was flagged during vetting but that he was misled about its depth.
That explanation has failed to stem criticism, as polls show declining public support for the prime minister following a series of policy reversals.
McSweeney’s exit removes a central figure in Starmer’s rise to power, but it remains unclear whether the resignation will contain the political damage.
Attention is now turning to who will replace him and whether further disclosures will intensify pressure on the prime minister.