“Chris Wormald will stand down as the cabinet secretary and head of the civil service by mutual agreement from today,” said a joint statement released by the government.
His departure comes after two top aides quit earlier this week over the row triggered by the appointment of Peter Mandelson as ambassador to Washington despite his links to the late US convicted sex offender Epstein.
The fallout from Mandelson’s appointment was sparked by emails showing that he had remained friends with Epstein long after the latter’s conviction in 2008. It is the most serious crisis of Starmer’s 19-month tenure.
Starmer’s chief of staff Morgan McSweeney, a Labour party stalwart, left on Sunday for advising Starmer to make the contentious Mandelson appointment.
Deprived of his closest adviser, Starmer was then left scrambling to shore up his premiership as another top aide, communications chief Tim Allan, quit on Monday just months into the role.
Wormald’s departure had been widely anticipated, and he will be replaced in the interim period by three people, including two women.
“The prime minister will appoint a new cabinet secretary shortly,” the government statement said.
Conservative leader Kemi Badenoch hit out at the “preposterous” handling of Wormald’s exit, noting it was coming just 14 months after he took on the role.
She accused Starmer of forcing him out.
Documents released on Jan 30 by the US Justice Department appeared to suggest that Mandelson had leaked confidential UK government information when he was a British minister to financier Epstein, including during the 2008 financial crisis.
The revelation placed intense pressure on Starmer and triggered a police investigation into Mandelson, 72, for alleged misconduct in a public office.
Starmer’s premiership looked precarious on Monday after losing his closest aides over the Mandelson saga, and Labour’s leader in Scotland Anas Sarwar called on him to quit.
But a co-ordinated show of support from senior ministers headed off any imminent rebellion.
Starmer is deeply unpopular with the public and trails Nigel Farage’s hard-right Reform UK party in polls, although the next general election is likely three years away.
He faces a difficult by-election later this month and key local polls in May.