Starmer, who has represented Holborn and St Pancras since 2015, added: “I will also continue, as I have done for a long time now with others, work on combating violence against women and girls; that is an issue that matters to me hugely. It’s work I started before I became an MP and it’s work I’m keen to continue after I’m an MP.”
His resignation will trigger a by-election — a big electoral test for Andy Burnham, his successor in Downing Street.
He follows other former prime ministers, including David Cameron and Tony Blair, in leaving the Commons soon after or immediately following their departure from No. 10 Downing Street.
The ex-PM held the Holborn and St Pancras seat in 2024 with an 11,572 majority, but faced a strong challenge from a left-wing independent and the Greens.
Zack Polanski’s left-wing environmentalists are likely to form the biggest challenge to Labour in the normally safe London seat.
A Green Party spokesperson suggested Polanski could contest the seat himself.
“Zack has always made it clear he would like to be a London MP. London has been his home for over 20 years,” they said.