LONDON: British Prime Minister Keir Starmer said on Friday he would not walk away, ​vowing to fight any challenge from his leading party rival, Andy Burnham, and potentially ushering in a new bout of political instability.

Burnham, the Greater Manchester mayor, won a decisive victory for Labour to claim a parliamentary seat in northwest England, and has signaled that he will use it to enter any contest to replace Starmer.

The scale of his victory in Makerfield in northwest England prompted more Labour lawmakers to say Starmer, unpopular and under pressure from the populist Reform UK in surveys, should consider stepping down to enable an orderly handover to Burnham.

Andy Burnham, the Greater Manchester mayor, won a decisive victory for Labour to claim a parliamentary seat in northwest England, and has signaled that he will use it to enter any contest to replace Prime Minister Keir Starmer.

That would mean Britain installing its seventh prime minister in just over a decade, the highest turnover in nearly two centuries — a reflection of voter anger at successive failures to improve living standards and public services and tackle illegal immigration.