In the wake of the publication of the report by senior civil servant Sue Gray, who investigated the allegations of parties being held in Downing Street amid strict nationwide coronavirus restrictions, Boris Johnson has been experiencing difficulties.
Gray accused No 10 of "serious failures of leadership and judgement", pointing at the "excessive" amounts of alcohol involved in what Johnson insists were "work events", not actual parties.
As No 10 continues to weather the "partygate" storm, four of the PM's senior aides have announced their resignation.
Here is a quick look at these aides and their reasoning.
Munira Mirza
Munira Mirza, the prime minister's director of policy, was the first No 10 senior aide to announce her resignation on Thursday. She decided to leave Downing Street due to Boris Johnson's harsh remarks about Sir Keir Starmer, the leader of the Labour Party.
On Monday, the embattled prime minister accused Starmer of failing to take action against late sex offender Jimmy Saville, a UK TV and radio personality who was accused of child sex abuse and rape. The majority of the allegations against him were made after his death in 2011; accusations made during his lifetime were largely dismissed or ignored.
Starmer was the director of public prosecutions from 2008 until 2013. Before Saville's death, the Crown Prosecution Service (CPS) decided not to prosecute him, and Johnson alleged on Monday that Starmer had a role in it. There was, however, no evidence to prove Starmer's involvement in this decision.
Later, Johnson admitted that Starmer had "nothing to do" with the Saville case, but failed to apologise.
Mirza voiced her discontent with the prime minister over the incident.
"I believe it was wrong for you to imply this week that Keir Starmer was personally responsible for allowing Jimmy Savile to escape justice. There was no fair or reasonable basis for that assertion," Mirza said in her resignation letter, blasting Johnson for failing to apologise for "the misleading impression you gave".
Shortly after her resignation, Chancellor Rishi Sunak (who is viewed by many as one of the likely successors to the prime minister) distanced himself from Johnson's remarks about Startmer and described Mirza as a "valued colleague" and said he was "sorry to see her leave government".
The same sentiment regarding Mirza's departure was voiced by Johnson himself.
"She's done an outstanding job and has been a wonderful colleague for a long time," the prime minister said when speaking to Channel 5 on the matter.
However, he said he could not agree with her description of his Starmer comments as "inappropriate and partisan".
"All that I've said is that the leader of the opposition apologised for the CPS's handling of that issue during his tenure and that's all frankly that needs to be said on that matter," Johnson explained.
Jack Doyle
Later in the day, Jack Doyle resigned as Downing Street's director of communication shortly after Mirza's surprise announcement.
He, however, specified that his decision had nothing to do with Johnson's remarks about Starmer, According to Doyle, he planned to step down after having served two years in the position.
"Recent weeks have taken a terrible toll on my family life," Doyle added, apparently referring to the "partygate" scandal rattling around Downing Street.
Reports suggested that Doyle was involved in the alleged parties - he is said to have handed out awards and given a speech during the infamous "Christmas party" in Downing Street. This fact is also said to have impacted his decision to leave.
BBC reported in December that Doyle had already offered to quit after he came under fire over "partygate" allegations, but the prime minister had refused to accept his resignation at the time.
"Jack Doyle has left government. He has made a huge contribution and the prime minister is immensely grateful for the work he has done," a No 10 spokesperson said of Doyle's exit.
Dan Rosenfield and Martin Reynolds
The prime minister's chief of staff, Dan Rosenfield, and Johnson's principal private secretary Martin Reynolds exited No 10 later Thursday.
A Downing Street spokesperson confirmed their departure and said that Johnson had accepted their resignation. Both are set to execute their duties until their successors are recruited.
"[The UK prime minister] has thanked [Rosenfield and Reynolds] for their significant contribution to government and No 10, including work on the pandemic response and economic recovery," the spokesperson said.
Neither Rosenfield nor Reynolds have revealed their reasons for quitting, but both are said to have organised the “bring your own booze” party in Downing Street that took place in March 2020.
BoJo's Troubles
This week, Boris Johnson announced that there will be a shake-up among the MPs over the "partygate" report by Sue Gray. However, many observers have already speculated that it was Mirza's resignation that forced the embattled prime minister to bring forward these plans.
Johnson is under fire as he is suspected of participating in some of the alleged parties that occurred in Downing Street from 2020 to 2021 when the country was plunged in strict coronavirus lockdown.
Amid the "partygate" fallout, several Tory MPs filed their letters of no confidence in Boris Johnson, with reports suggesting that over a dozen of Conservative lawmakers did so, and more are considering to join their colleagues.
In order for a no-confidence vote to be triggered, Sir Graham Brady, the chairman of the 1922 Committee, needs to receive at least 54 letters. The committee, apart from providing a way for Tory backbenchers to coordinate and discuss their views independently from the frontbenchers, plays an important role as the body representing the views of the party's parliamentary rank.