Morgan McSweeney has dramatically quit as Sir Keir Starmer's chief of staff, after mounting scrutiny over his role in Lord Mandelson's appointment as the UK's ambassador to the US.
The PM's adviser had been coming under pressure after pushing for the former minister to be given the job, despite the peer's relationship with convicted sex offender Jeffrey Epstein being publicly known about at the time.
McSweeney said he did not oversee the vetting but wanted to take "full responsibility" for advising the prime minister to appoint him.
It leaves Sir Keir battling to shore up his premiership as he continues to face anger from Labour MPs over his decision to hire the peer for the Washington role.
Sir Keir sacked Lord Mandelson in September, after emails emerged showing he sent supportive messages to Epstein as he faced charges for sex offences.
