Oris Johnson clung to office Tuesday night after the shocking resignation of his chancellor and health minister.
Rishi Sunak left the cabinet minutes after Sajid Javid stepped down.
Their departure plunged Johnson’s premiership into its worst crisis yet.
Mr Javid has resigned as health minister, saying in a letter to Boris Johnson that after last month’s confidence vote “it is clear to me that this situation will not change under your leadership – and that is why you have lost my confidence”.
In a tweet, he said: “I have spoken with the Prime Minister to tender my resignation as Secretary of State for Health and Social Care.
“It has been a tremendous privilege to serve in this role, but I regret not being able to continue in good conscience.”
Minutes later, Mr Sunak tweeted: “The public rightly expects the government to be run properly, competently and seriously.
“I recognize that this may be my last ministerial job, but I believe these standards are worth fighting for and that is why I am resigning.”
In his resignation letter, Sajid Javid told the prime minister that the recent confidence vote was a “moment for humility, grip and new direction”.
“I am sorry to say, however, that it is clear to me that this situation will not change under your leadership – which is why you have lost my trust.”
He also told Boris Johnson: “You will forever be credited with averting the threat of Corbynism and breaking the deadlock over Brexit.”
He continued: “The country needs a strong and principled conservative party, and the party is bigger than any individual. I have served you loyally and as a friend, but we all serve the country first.
“If you have to choose between those loyalties, there can only be one answer.”