Embattled Boris Johnson has started to replace the aides following a mass walkout amid the Downing Street Partygate scandal.
Downing Street 's woes reached new heights when it emerged Sue Gray was investigating 16 allegations of lockdown-breaking events, with 12 subject to a Metropolitan Police probe.
The top civil servant warned of "a serious failure to observe not just the high standards expected of those working at the heart of Government, but also of the standards expected of the entire British population at the time" in her interim report.
Several top members of Mr Johnson's staff quit last week, leaving him to fill his ranks as he looks to rebuild trust the public.
He also needs to win over his mutinous MPs to see off the threat of a Tory leadership contest.
Which aides walked out on Boris Johnson and why?
Mr Johnson lost five of his aides last week: Munira Mirza, Martin Reynolds, Dan Rosenfield, Jack Doyle and Elena Narozanski.
Policy chief Ms Mirza, a longstanding aide, criticised the PM over "scurrilous" claims he made about Labour leader Keir Starmer, who he accused of failing to prosecute paedophile Jimmy Savile.
In her resignation letter, she said: "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. This was not the normal cut-and-thrust of politics; it was an inappropriate and partisan reference to a horrendous case of child sex abuse.
"You tried to clarify your position today but, despite my urging, you did not apologise for the misleading impression you gave", she added.
Ms Narozanski also worked in the policy unit but has not commented publicly on her reasons for quitting.
Chief of Staff Dan Rosenfield and the PM's principal private secretary Martin Reynolds both offered their resignations after being caught up in the Partygate row.
No10 spin chief Jack Doyle is said to have told aides the parties saga had taken a "terrible toll" on his family life.
Who are Boris Johnson's new aides?
Steve Barclay MP
Steve Barclay already has two jobs, and will now be adding a third as Prime Minister Boris Johnson's new Chief of Staff.
Cabinet Office minister Mr Barclay will be replacing Dan Rosenfield and will be undertaking what No 10 describe as the task of creating a "new Office of the Prime Minister and the Cabinet Office".
In a tweet, he said: "It is an honour to have been asked by the PM to serve as Chief of Staff for No10 Downing Street alongside my responsibilities in the Cabinet Office.
"I am looking forward to working with the PM, Ministers and Parliamentary colleagues on the issues that matter most to our country".
As well as his new role, and his job as an MP, Barclay is also the Chancellor of the Duchy of Lancaster, raising eyebrows about how he will be able to squeeze all of his responsibilities in effectively.
Guto Harri
Guto Harri will be taking over as Boris Johnson's communications chief, with the former BBC journalist having worked with Johnson as his Chief of Staff and spokesperson during his time as Mayor of London.
Mr Harri began working for GB News but left the outlet following a row in which he took the knee as a sign of support for Black Lives Matter.
Speaking to Welsh-speaking magazine Golwg.360, Harri claimed that during a meeting between himself and Prime Minister, the nation's leader bizarrely broke out in a rendition of Gloria Gaynor’s 'I Will Survive'.
The Welshman said: "I asked: ‘Are you going to survive, Boris?’
“And he said in his deep voice – slow and purposeful – starting to sing a little while finishing the sentence and saying: ‘I will survive.’
However, No 10 has already been forced to defend the appointment of Mr Harri who previously worked for a firm advising Chinese tech giant Huawei, which will be stripped from the UK's 5g network by 2027.
Asked if there were concerns about conflicts of interest or security, a Downing Street spokesperson said: "No. He provided advice to the clients of a private company. This is entirely legitimate, it's in the public domain.
“We wouldn’t exclude from government someone with valuable experience and expertise.
“Our position on Huawei is clear. We have strict controls in the way that Huawei is currently deployed."
The spokesperson also stressed that everyone joining the government goes through security checks.
Following the backlash over allegations of lockdown gatherings, Mr Johnson said of his new appointments: "This week I promised change so that we can get on with the job the British public elected us to do."
He also discussed his hopes that the new appointments would be able to aid his levelling up agenda, which has faced a slew of setbacks and criticisms.
