Prime Minister Keir Starmer announced his resignation on Monday, less than two years after leading the Labour Party to a significant election victory. His departure amid mounting internal pressure from within his own party triggers a race for the United Kingdom's seventh prime minister in just over a decade.

Starmer's resignation comes after weeks of weakening political standing, exacerbated by disappointing local election results. The final catalyst was a decisive parliamentary by-election victory in Makerfield secured by challenger and Greater Manchester Mayor Andy Burnham, which intensified the rebellion within the Labour Party.

In an emotional address, Starmer stated he would remain as prime minister until a new Labour leader is selected. The formal leadership contest is slated to commence on July 9 and is expected to conclude before the UK Parliament's summer recess.

Starmer's resignation places Andy Burnham as an immediate frontrunner to succeed him. However, other prominent Labour figures, including former Health Secretary Wes Streeting, are anticipated to consider running for the leadership. To appear on the ballot, a candidate must secure nominations from 81 Labour Members of Parliament.

This change in leadership continues a period of significant political instability for the UK. Since 2016, the country has experienced a rapid succession of prime ministers, with an average tenure of approximately 18 months. This contrasts sharply with the longer periods served by leaders like Margaret Thatcher and Tony Blair, who each led for over a decade.

The recent history of UK prime ministers includes David Cameron, who resigned in 2016 following the Brexit referendum. Theresa May followed, resigning in 2019 after failing to gain parliamentary support for her Brexit withdrawal agreement. Boris Johnson resigned in 2022 amid numerous scandals and ministerial resignations.

Liz Truss briefly held the position in 2022, setting a record for the shortest premiership at just 49 days, marked by market turmoil stemming from her government's economic policies. Rishi Sunak departed office after the Conservative Party's substantial defeat in the 2024 general election, paving the way for Starmer's Labour government.

The upcoming leadership contest could either lead to an extended summer campaign or a more rapid selection process, depending on the number of candidates who can gather the necessary nominations. The outcome will determine who becomes the seventh prime minister in ten years and faces the ongoing political and economic challenges confronting the nation.