British Prime Minister Boris Johnson Thursday resigned after the defections plunged the Conservative Party-led government into a deeper political crisis. The decision to step down comes after one of his closest allies, Treasury Chief Nadhim Zahawi, told the prime minister to resign for the good of the country, AP reported.

The prime minister is expected to make a statement to the country later today, his office said.

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His resignation will trigger an internal election to pick a new leader of the Conservative Party, who will also be the next prime minister. That process is likely to take place over the summer.

Johnson signalled that he intends to stay in office until that concludes. Such a move would be controversial, and critics say he should not be allowed to remain even as caretaker prime minister.

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“Now PM has finally done the decent thing he needs to hand in the seals of office, apologise to Her Majesty (Queen Elizabeth II), allow her to appoint a Caretaker under whom Ministers can serve, so the Conservative Party can choose a new leader properly,” George Freeman, who quit as science minister on Thursday, said in a tweet.

Zahawi, who was promoted earlier this week as Johnson tried to shore up his Cabinet, said he and a group of colleagues had privately expressed their concerns to the prime minister on Wednesday and he decided to go public after Johnson ignored the advice to resign.

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“I am heartbroken that he hasn’t listened and that he is now undermining the incredible achievements of this government,” Zahawi said in a letter posted on Twitter. “But the country deserves a government that is not only stable, but which acts with integrity.”

Thursday morning’s resignations meant that 50 Cabinet secretaries, ministers and lower-level officials had quit the government over two days, often castigating the prime minister for his lack of integrity.

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With more than 20 positions unfilled, the crisis had stalled the business of some parliamentary committees because there were no ministers available to speak on the government’s behalf.

It is a humiliating defeat for Johnson, who succeeded in leading Britain out of the European Union and was credited with rolling out one of the world’s most successful mass vaccination campaigns to combat Covid-19.