Tim Allan, Keir Starmer's communications director, has resigned after just five months in the role, his resignation coming a day after that of the prime minister's chief of staff, Morgan McSweeney.

Allan said in a brief statement: "I have decided to resign to allow for the building of a new team. I wish the prime minister and his team every success."

The resignation is another blow to Starmer's position amid a fierce debate over the decision to make Peter Mandelson ambassador to Washington, despite his close ties to convicted child sex offender Jeffrey Epstein.

Starmer addressed Downing Street staff on Monday to reiterate his regret at Mandelson's appointment, while insisting his government could "move on from here".

Allan, former deputy press secretary to Tony Blair who later founded PR agency Portland, returned to Downing Street in September as part of the recent reshuffle of Starmer's team, in which Darren Jones was also moved to the Prime Minister's office from the Treasury.

Allan replaced James Lyons, who had been director of strategic communications for just a year. Shortly after Allan arrived in the role, Steph Driver, who was the No. 10 head of day-to-day communications, resigned amid concerns that Allan had been recruited over her.

Allan had been a somewhat controversial appointment, partly because of some of the clients he had taken over from Portland. But the loss of two senior members of staff in less than 24 hours will heighten the sense that Starmer's Downing Street operation is in free fall.