ASHTON-IN-MAKERFIELD, United Kingdom: Counting was under way late Thursday in a historic UK by-election which could determine embattled Prime Minister Keir Starmer’s future, as a Labour rival eyeing a leadership bid vies for a parliamentary seat.

Greater Manchester mayor Andy Burnham, a veteran of the ruling center-left Labour party, is seeking to win the contest for the Makerfield constituency in northwestern England.

If successful, he can then launch his widely anticipated attempt to oust Starmer as party leader and snatch the keys to Downing Street.

“Let’s vote for positive change that this country needs, let’s forever associate this area, this constituency, with having brought a change to British politics that it’s long needed,” Burnham, who hails from the region, said in a final campaign video posted on social media.

Counting began shortly after polling stations closed at 10:00 p.m. (2100 GMT), some 15 hours after opening.