British Prime Minister Keir Starmer’s chief of staff Morgan McSweeney has quit, he said in a statement on Sunday, as pressure intensifies on Starmer over his appointment of Peter Mandelson as ambassador to the United States.
Starmer is facing what is widely seen as the gravest crisis of his 18 months in power over his decision to send Mandelson to Washington in 2024, after files revealed the extent of Mandelson’s relationship with the late sex offender Jeffrey Epstein.
With polls showing Starmer is already hugely unpopular with voters, some in his own party are openly questioning his judgment and his future, and it remains to be seen whether McSweeney’s exit will be enough to silence his critics.
McSweeney said it was right for him to resign because Starmer had appointed Mandelson on his advice.
“The decision to appoint Peter Mandelson was wrong. He has damaged our party, our country and trust in politics itself,” McSweeney said in a statement.
“When asked, I advised the Prime Minister to make that appointment and I take full responsibility for that advice.”
Starmer has spent the last week defending McSweeney, a strategy that could prompt further questions about his own judgment. In a statement on Sunday, Starmer said it had been “an honour” working with McSweeney.
New evidence about Mandelson’s relationship with Epstein came to light in the last ten days, opening an old wound for Starmer and his Labour Party and sparking a police investigation into Mandelson’s alleged misconduct in public office. The files suggested the former ambassador had leaked government documents to Epstein in 2009 and 2010.
McSweeney, who was a protege and friend of Mandelson, was accused by some Labour lawmakers and his political opponents of failing to ensure that there were proper background checks when he was appointed.
He had held the role of chief of staff since October 2024, when he was handed the job following the resignation of Sue Gray following a row over pay and donations.

