Prime Minister Keir Starmer sought to quell a mounting rebellion in his party on Monday by vowing to prove the doubters wrong and stay in power ?to avoid plunging Britain into a new political crisis.

A growing number of Labour ?lawmakers have ?turned on Starmer after his party suffered the worst local election ?results for a governing party in more than three decades last week, prompting a former junior minister to threaten to seek a leadership contest if he fails to offer ?radical change.

Starmer sought to show he had got the message, saying in an impassioned speech that ¡°incremental ?change won¡¯t cut it¡± in a country that has suffered two decades of economic stagnation and mounting social tensions.

¡°I know that people are frustrated by ?the state of Britain. Frustrated by ?politics, and some people are frustrated with me,¡± he said in a speech in London. ¡°I know I have my doubters ?and I know I need ?to prove them wrong. And I will.¡±

Starmer won one ?of the largest parliamentary majorities in modern British history in 2024 with ?promises to ?expand the economy, lower illegal immigration, and cut waiting lists in the state-run health service.

However, progress has been hampered by policy U-turns, perceptions among some in his party that he is unwilling to take difficult decisions, and a series of political ?scandals, contributing to some of the lowest approval ratings of any British prime minister.

The uncertainty has pushed up borrowing costs as investors fear that Starmer could be replaced by a more left-wing leader willing to borrow more ¡ª a rerun of the chaos that ensued in the latter ?years ?of the previous Conservative Party which struggled to govern.

The populist Reform ?U.K., led by Brexit campaigner Nigel Farage, has now led national opinion polls for more ?than a year and at the local elections last week, the left-wing Green Party also made large advances in British cities.

Starmer said Labour could not afford to turn on each other when the country was facing ¡°very dangerous opponents¡± who want ¡°more ?grievance politics, more division, more pointing at Britain¡¯s problems, looking not for solutions but for someone to blame.¡±

¡°If we don¡¯t get this right, our country will go down a very dark path,¡± he said.