Newly appointed Chancellor of the Exchequer Nadim Zahawi arrives at the Treasury on July 6, 2022 in London, England. Photo: VCG

Boris Johnson on Wednesday refused to quit as British prime minister, despite a slew of resignations from his scandal-hit government, piling on pressure as he faced a grilling from angry MPs.

The 58-year-old leader promised to "deliver" on his "mandate." 

Health Secretary Sajid Javid and Chancellor of the Exchequer Rishi Sunak resigned on Tuesday in protest against Johnson's leadership as a barrage of scandals left the Conservative government reeling.

Both said they could no longer tolerate the culture of scandal that has stalked Johnson for months, including lockdown lawbreaking in Downing Street that enraged the public who followed the rules.

At the weekly session of Prime Minister's Questions in parliament, MPs from all sides rounded on Johnson.

But brushing off calls to resign, he told MPs, "Frankly, the job of a prime minister in difficult circumstances when you have been handed a colossal mandate is to keep going and that's what I'm going to do."

Johnson has suffered an exodus of ministers in just 24 hours and later faced an hours-long grilling from the chairs of the House of Commons' most powerful committees, including some of his most virulent critics in the Tory ranks.

Sunak and Javid's departures came just minutes after Johnson apologized for appointing a senior Conservative, who quit his post last week after he was accused of drunkenly groping two men.

Former education secretary Nadhim Zahawi was immediately handed the finance brief. "You don't go into this job to have an easy life," Zahawi told Sky News. 

Days of shifting explanations had followed the resignation of deputy chief whip Chris Pincher. Downing Street at first denied Johnson knew of prior allegations against Pincher when appointing him in February. But by Tuesday, that defense had collapsed after a former top civil servant said Johnson, as foreign minister, was told in 2019 about another incident involving his ally.

Minister for Children and Families Will Quince quit ­early Wednesday, saying he was ­given the inaccurate information before having to defend the government in a round of media interviews on Monday.

That triggered a new wave of more than a dozen resignations, and the withdrawal of support from previously loyal MPs.  

The Pincher affair was the "icing on the cake" for Sunak and Javid, Tory MP Andrew Bridgen, a strident Johnson critic, told Sky News.