LONDON — Four senior aides to Britain’s Boris Johnson have resigned from Downing Street within hours of each other amid growing pressure on the prime minister.

Director of communications Jack Doyle confirmed his exit shortly after the departure of policy head Munira Mirza.

They were followed by chief of staff Dan Rosenfield and senior civil servant Martin Reynolds.

The top aides' resignations came as Mr Johnson faces increasing questions over his leadership from within his party.

Mr 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 Mr Rosenfield had offered his resignation to the prime minister earlier on Thursday, but would stay on while his successor was found.

And Mr Reynolds - the prime minister's principal private secretary - will do the same, but then return to a role at the Foreign Office.

A number of MPs supportive of the prime minister have been tweeting praise, suggesting Mr Johnson was responsible for making necessary staff changes following a damning report by civil servant Sue Gray into rule-breaking parties in No 10 during the pandemic.

However, Ms Mirza quit over the PM's false claim that Sir Keir Starmer failed to prosecute Jimmy Savile when he was director of public prosecutions, and his refusal to apologize.

Chancellor Rishi Sunak publicly distanced himself from the PM's original comment, saying: "Being honest, I wouldn't have said it."

And asked if Mr Johnson should apologise, he said: "That's for the prime minister to decide."

Labour's deputy leader Angela Rayner said: "With [Mr Johnson's] senior advisers and aides quitting, perhaps it is finally time for him to look in the mirror and consider if he might just be the problem."

The resignations come as backbench unrest is growing within the Conservative Party.

The BBC is aware of 17 Tory MPs who have submitted letters of no confidence in the prime minister - 54 are needed to trigger a leadership contest.

Many have cited the PM's participation in parties with staff in No 10 during lockdowns as their motivation to challenge Mr Johnson.

These gatherings included a "bring your own booze" garden party in May 2020 - the email invite to which was sent by Mr Reynolds.

The Metropolitan Police has launched an investigation into 12 of the parties and a full report by Ms Gray is expected to be published afterwards.

Other MPs have pointed to the PM's remark about Sir Keir as one of their reasons for writing a letter.

In a debate on the findings of a report into lockdown parties on Monday, Mr Johnson accused the Labour leader of spending "most of his time" as director of public prosecutions (DPP) "prosecuting journalists and failing to prosecute Jimmy Savile", despite having no evidence to back up the claim.

Savile was a serial sexual abuser who attacked hundreds of women and children at locations including hospitals, schools and the BBC.

By Thursday, Mr Johnson appeared to have backed down, telling reporters he had not been talking about Sir Keir's "personal record" when he was DPP, adding: "I totally understand that he had nothing to do personally with those decisions."

But in her resignation letter, published by the Spectator, Ms Mirza said the PM should have apologized for the misleading remarks.

Speaking to Channel 5 News after Ms Mirza quit — but before the news of the other resignations was made public — the prime minister said he was "sorry to lose Munira".

But asked about her conclusion that his remarks about Sir Keir had been "inappropriate and partisan", Mr Johnson replied: "Well, I don't agree with that."

He said: "No-one is commenting, least of all me, about the personal involvement of the leader of the opposition in the handling of that case.

"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."

Downing Street confirmed that Tory MP Andrew Griffith would take over from Ms Mirza as the head of the PM's policy unit, as well as become the minister for policy.

Speaking to BBC Newsnight, ex-Tory foreign secretary Malcolm Rifkind criticised Mr Johnson's "very hollow" political judgement and described the situation as "not so much the end of the beginning as the beginning of the end". — BBC