British Prime Minister Boris Johnson’s inner circle has been rocked by a host of resignations after four senior aides quit on the same day.

Chief of staff Dan Rosenfield and Johnson’s principal private secretary Martin Reynolds are the latest to have their exit confirmed on a day of turmoil for the embattled prime minister.

They follow director of communications Jack Doyle in resigning on Thursday, along with Munira Mirza, one of Johnson’s most loyal and longstanding advisers who walked out over the prime minister’s use of a “scurrilous” Jimmy Savile smear against Labour leader Sir Keir Starmer.

Mirza was said to have quit in outrage at his “inappropriate and partisan reference to a horrendous case of child sex abuse.” During an interview on Thursday, Johnson backtracked on the widely criticised and debunked claim that the Labour leader failed to prosecute Savile.

Johnson’s standing has been badly damaged by a damning report released this week into allegations of pandemic lockdown-breaking parties.

The drip, drip of calls for Johnson to quit have grown louder weeks after the so-called Partygate scandal first erupted.

A Downing Street spokeswoman said: “Dan Rosenfield offered his resignation to the prime minister earlier today, which has been accepted. Martin Reynolds also informed the prime minister of his intention to stand down from his role as principal private secretary and the prime minister has agreed to this.

He has thanked them both for their significant contribution to government and No 10, including work on the pandemic response and economic recovery. They will continue in their roles while successors are appointed, and recruitment for both posts is under way.”

Reynolds will return to the Foreign Office, officials said.