LONDON, United Kingdom (AFP)—Britain’s Prime Minister Keir Starmer on Monday vowed to prove his doubters wrong and stem mounting calls for him to step down after disastrous local and regional elections for his ruling Labour party.

But more than 50 of his own MPs were unconvinced by his pledge to make the party bolder and better to assuage disgruntled voters impatient for change, and called for him to quit.

By Monday evening, at least 55 of the 400 or so Labour members of parliament urged him to step down, including three government aides who resigned their positions.