A few days before Britain’s Queen Elizabeth II celebrates 70 years on the throne, “an unprecedented reign that has made her a symbol of stability as the United Kingdom navigated an age of uncertainty,” as The Associated Press puts it, British Prime Minister Boris Johnson’s office is a chaotic mess.

Four of Johnson’s most senior aides exited Downing Street on Thursday, including his long-term policy director, Munira Mirza, who released a scathing resignation letter upon her departure. 

Along with Mirza — who has worked for Johnson since 2008 and is so central to his politics she is sometimes called “Boris’s brain” — Thursday’s departures included communications director Jack Doyle, chief of staff Dan Rosenfield, and Johnson’s principle private secretary Martin Reynolds. A more junior policy adviser, Elena Narozanski, quit Friday morning, BBC News reports. 

Doyle, Rosenfield, and Reynolds were all implicated in “Partygate,” the string of parties held at No. 10 Downing Street during COVID-19 lockdowns, when other Britons were barred from gathering. Johnson allies said their departures were part of a housecleaning after a report by senior civil servant Sue Gray slapped Johnson’s government for “failures of leadership and judgment.” Scotland Yard is also investigating 12 of the Downing Street lockdown parties. 

Mirza, though, made clear in her letter that she was leaving because of comments Johnson made about opposition Labour leader Sir Keir Starmer on Monday. Johnson falsely accused Starmer, a former director of public prosecutions, of failing to prosecute popular television personality Jimmy Savile, revealed after his death to have been a notorious serial child abuser. 

“You are a better man than many of your detractors will ever understand, which is why it is so desperately sad that you let yourself down by making a scurrilous accusation against the leader of the opposition,” Mirza wrote in her resignation letter. “This was not the usual cut and thrust of politics; it was an inappropriate and partisan reference to a horrendous case of child sex abuse,” and “despite my urging, you did not apologize for the misleading impression you gave.”

At least 17 members of Johnson’s Conservative Party have submitted letters of no confidence in the prime minister, BBC News reports. Asked about Johnson’s Savile comment, Chancellor Rishi Sunak, seen as a possible successor to Johnson, said, “Being honest, I wouldn’t have said it,” adding “I’m glad that the prime minister clarified what he meant.”