Keir Starmer to leave UK Parliament, triggering London byelection

Former British prime minister Keir Starmer has announced that he will leave Parliament, triggering a byelection in his north London constituency of Holborn and St Pancras.

Starmer said on September 1, 2026, that it was the right time to “pass the baton to a successor” after deciding to concentrate on work outside the House of Commons. He identified international affairs—including defence, security, trade and technology—as priorities, alongside continued work to combat violence against women and girls.

The decision reverses the position Starmer took when he resigned as prime minister in July, when he said he intended to remain a backbench MP until the next general election. He said he would not endorse a candidate in the Labour selection contest to replace him.

Starmer has represented Holborn and St Pancras since 2015. He won the seat at the most recent general election with a majority of 11,572 votes, according to the Guardian’s reporting.

His departure creates a politically significant contest in London. The Green Party has not ruled out its leader, Zack Polanski, seeking the seat, while Labour will choose a new candidate through its local selection process.

Starmer became Labour leader in 2020 and led the party to a landslide general-election victory in 2024. His decision to leave the Commons follows Andy Burnham’s succession as prime minister and opens a new phase in both Starmer’s public career and the competition for his former constituency.