Boris Johnson held off a challenge by rebels to remain leader of the governing Conservative Party, though the hollow victory leaves the British prime minister weakened and exposed the divisions that may ultimately sink his premiership.

In a secret ballot in the U.K. Parliament on Monday evening, 211 Tory MPs voted for Johnson compared with 148 against. The rebellion was bigger than the one suffered by predecessor Theresa May, who was ousted as prime minister six months later after failing to unite the party.

Pressure had been building on Johnson for weeks over so-called partygate, events in Downing Street during the pandemic for which the 57-year-old prime minister received a police fine. A report by senior civil servant Sue Gray found many of them shouldn’t have been allowed. But discontent among MPs goes far beyond the illegal gatherings, and Johnson’s leadership is likely to remain unsteady despite winning the vote.