LONDON: British PM 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. The departure of McSweeney, 48, the political strategist who was instrumental in Starmer’s rise to power, throws the future direction of the govt into doubt, less than two years after the Labour Party won one of the largest parliamentary majorities in modern British history.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. “When asked, I advised the PM 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 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 10 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 govt documents to Epstein in 2009 and 2010. Labour members of parliament had called for McSweeney’s resignation, blaming him for the appointment of Mandelson. A number of lawmakers have called for Starmer to resign. “Starmer has to take responsibility for his own terrible decisions,” said Kemi Badenoch, leader of the opposition Conservative PartyReuters