British Prime Minister Boris Johnson Friday invoked Disney's "The Lion King", insisting "change is good" as he rallied his dwindling inner circle in the fallout over lockdown-breaking parties held in his Downing Street office.

Chief policy advisor Munira Mirza unexpectedly quit on Thursday, delivering a serious blow to the embattled leader and sparking three more resignations in his top team.

A fifth aide -- Elena Narozanski, who worked under Mirza -- quit on Friday, although the government said that Johnson was delivering on a promised clearout following the "partygate" revelations.

But the manner of the departures, particularly that of long-serving loyalist Mirza, has increased the sense that Downing Street is rudderless as Johnson fends off calls for his resignation.

"It's a Downing Street in chaos," University of Liverpool politics professor Jon Tonge told AFP.

"Every time he tries to restore order, there's a new set of problems."

Health Secretary Sajid Javid joined finance minister Rishi Sunak in disowning an incendiary remark by Johnson against opposition Labour leader Keir Starmer that sparked Mirza's resignation.

Johnson this week linked Starmer -- who was formerly the chief prosecutor for England and Wales -- to the failure by UK authorities to charge late TV host Jimmy Savile over hundreds of child sex offences.

Heading into UK local elections in May, Labour has built a double-digit lead over Johnson's Conservatives, on the back of the partygate scandal and a squeeze to living standards caused by surging inflation.

Javid told Sky News that the Labour leader had done a "good job" as director of public prosecutions, and deserved "absolute respect" for his work in the post.

Battling to get back on the front foot, Johnson used a line from the Disney movie "The Lion King" as he addressed his remaining staff in Downing Street.

 'Meltdown in Downing Street'

"Change is good," he declared, according to his official spokesman, a reference to the popular animated film.

"You've seen the prime minister set out the need for change and his recognition that there have been misjudgements," the spokesman told reporters.

Eleven Conservative MPs have called publicly for Johnson to quit, as police investigate a series of parties held in Downing Street while the rest of the country was enduring Covid lockdowns.

While Johnson's senior ministers continue to stand by him, signs of disaffection are growing clearer including from Sunak, who is tipped as a leading contender to replace him.

Addressing the Savile controversy, the chancellor said in a televised rebuke: "I wouldn't have said it and I'm glad the prime minister clarified what he meant."

Thursday's roll call of resignations prompted the right-wing Daily Mail tabloid, which is normally supportive of the government, to headline its front page "Meltdown in Downing Street".

Other papers, while prominently covering the staff exodus, led on an impending surge in household energy bills which forced Sunak on Thursday to announce a package of financial support.

"Britons facing biggest drop in living standards," headlined The Times, underlining the political jeopardy that Johnson faces on multiple fronts.

Downing Street confirmed that chief of staff Dan Rosenfield was leaving, just over a year after he took on the role with a brief to professionalise Johnson's chaotic operation.

His resignation came after a long-awaited inquiry this week condemned "failures of leadership" over the Downing Street parties.

Also out was Martin Reynolds -- the head of Johnson's private office -- who sent a now-notorious email in May 2020 urging Downing Street staff to "bring your own booze" to one lockdown gathering.

Johnson's director of communications Jack Doyle was another departure. According to the Daily Mail, Doyle told colleagues: "Recent weeks have taken a terrible toll on my family life."