Sir Keir Starmer has appointed joint acting chiefs of staff following Morgan McSweeney's departure, it has been widely reported.

Vidhya Alakeson and Jill Cuthbertson, who were Mr McSweeney's deputies, are said to have taken up the positions. McSweeney quit as chief of staff earlier today, saying he takes "full responsibility" for advising the prime minister to appoint Peter Mandelson as US ambassador last year.

It comes after police launched a criminal investigation into claims Mandelson passed sensitive information to convicted sex offender Jeffrey Epstein.

Mandelson was sacked from his position in September following reports that he had continued his friendship with Epstein after his 2008 conviction. But after millions of new documents were released as part of the so-called Epstein files last week, the issue was brought back into the spotlight.

Starmer's reported new appointee Vidhya Alakeson has responsibility for policy and delivery and has managed Downing Street's external relationships. Before Labour entered office, she forged ties with the business community as the party's director of external relations.

The former Resolution Foundation think tank deputy chief executive served in the No 10 strategy unit and in the Treasury during the last Labour government.

Jill Cuthbertson has managed the Prime Minister's diary and has been described as the ultimate gatekeeper to Sir Keir. She ran his office when he was leader of the opposition, having previously held similar roles for former Labour leaders Ed Miliband and Gordon Brown.

In a statement following his resignation, Mr McSweeney said: "The decision to appoint Peter Mandelson was wrong. He has damaged our party, our country and trust in politics itself. When asked, I advised the prime minister to make that appointment and I take full responsibility for that advice.

"In public life, responsibility must be owned when it matters most, not just when it is most convenient. In the circumstances, the only honourable course is to step aside."

On Thursday, Starmer apologised to the victims of Jeffrey Epstein for believing Lord Mandelson's "lies" and appointing him as the UK's ambassador to the US.