Another aide of UK Prime Minister Boris Johnson has quit. This takes the total number of resignations at Downing Street to five as the embattled British premier struggles to reset his government following the "Partygate" scandal that has put made his position vulnerable. The PM faces increasing questions over his leadership from within his party.

The string of resignations continued today with the ruling Conservative Party's website reporting that Elena Narozanski has become the second adviser to quit the No 10 Downing Street policy unit.

Boris Johnson's longstanding policy chief Munira Mirza, Chief of Staff Dan Rosenfield, Principal Private Secretary Martin Reynolds, and Communications Director Jack Doyle left their posts within hours of each other yesterday, days after a damning investigation revealed that the UK PM hosted multiple parties at the Downing Street as the country lived under a strict Covid lockdown.

Former Downing Street aide Nikki da Costa said Elena Narozanski is "one of the most principled women I know."

"Another big loss to the policy unit," Ms da Costa said.

Meanwhile, Business and Energy Secretary Greg Hands said today that Prime Minister Johnson is taking charge of his Downing Street team by making changes after the scandal.

Asked what was going on in Downing Street, Greg Hands told British broadcaster Sky that "resignations have been made, resignations have been accepted."

Senior Tory member of Parliament Huw Merriman, who chairs the Commons Transport Committee, said he was "deeply troubled" by the situation, and told Johnson to improve or leave Downing Street for good.

Jack Doyle confirmed his exit shortly after the departure of Pakistan-origin Munira Mirza. They were followed by Dan Rosenfield and Martin Reynolds, the BBC reported today.

Doyle told staff that "recent weeks have taken a terrible toll on my family life", but that he had always intended to leave after two years.

A statement from a No 10 spokeswoman said Rosenfield had offered his resignation to the Prime Minister earlier on Thursday but would stay on until his successor is found. Reynolds will do the same, but then return to a role at the Foreign Office, the report said.

Mirza's exit is the most consequential. She was one of Johnson's long-standing allies and a key political player who helped shape the Prime Minister's platform - some of which made her unpopular with other members of his ruling Conservative Party.

Johnson's former adviser Dominic Cummings claimed Mirza's departure was "an unmistakable signal the bunker is collapsing and this PM is finished". He urged ministers to show a similar "flicker of moral courage" and resign.

Chancellor Rishi Sunak publicly distanced himself from Johnson's original comment, saying: "Being honest, I wouldn't have said it." Asked if Johnson should apologise, the Indian-origin leader said, "That's for the Prime Minister to decide."

Rishi Sunak has previously declined to criticise Johnson directly through the weeks of revelations about lockdown-busting parties in Downing Street, though he has acknowledged that mistakes were made.

The pressure on Johnson to step down has been increasing among members of his Conservative Party after a series of missteps and allegations that he and his team held rule-breaking parties during the pandemic.

Labour's deputy leader Angela Rayner said, "No amount of reorganising Downing Street can clean up the sleaze that comes straight from the top."

Three Conservative MPs went public on Wednesday with their intention to submit letters of no confidence in the Prime Minister. If Johnson loses such a vote, which could be held within days, his premiership would be over.