LONDON — Britain’s most senior civil servant is negotiating his exit from government as Keir Starmer battles to steady his crisis-hit government.

Chris Wormald is expected to resign as cabinet secretary after just over a year in post, according to three U.K. officials, granted anonymity to talk about internal discussions. The announcement could come Tuesday, although the officials stressed the timing is still to be decided.

Wormald will be the third senior figure to leave Starmer’s Downing Street at a crucial moment for his premiership, and as the prime minister continues to face questions about his judgement in appointing Peter Mandelson as U.K. ambassador to Washington.

Morgan McSweeney resigned as the prime minister’s chief of staff Sunday after recommending the appointment, and Starmer’s Director of Communications Tim Allan stepped down Monday having served in post for just five months.

The cabinet secretary advises the prime minister and other senior members of the government. It is usually combined with the role of head of the civil service.

Wormald previously served as permanent secretary at the Department of Health and Social Care, running the department during the coronavirus pandemic.