British Prime Minister Keir Starmer announced his resignation on Monday after facing intense pressure following the political rise of Labour rival Andy Burnham.
Starmer's departure will make him the sixth UK prime minister in a decade to leave office before completing a full term, highlighting the political instability that has persisted since the Brexit vote in 2016.
He said he would remain as caretaker Prime Minister until Labour selects a new leader in the coming weeks.
Delivering a brief statement from 10 Downing Street to announce his departure, Starmer appeared emotional, with his voice breaking toward the end of his remarks.
The process to replace Starmer will begin with his formal resignation on July 9, the date he said he would step down as prime minister and Labour leader.
A successor is expected to be in place by the time Parliament returns from its summer recess in September, ensuring a new prime minister is installed before lawmakers resume business.