Keir Starmer announces he is standing down as MP

Former Prime Minister Sir Keir Starmer has announced he is to stand down as an MP to focus on a role in international affairs.

The move will trigger a by-election in the London seat of Holborn and St Pancras, long a Labour stronghold, which he has represented since 2015.

Sir Keir, who left Downing Street in July, had previously said he would stay on as an MP until the next UK general election, which is not due until 2029.

But in a surprise statement hours before his successor Andy Burnham made his debut in the House of Commons, he said he was resigning to work on issues such as international affairs and violence against women and girls.

Paying tribute to his predecessor, Burnham highlighted Sir Keir's work with Ukraine and the Hillsborough Law drawn up under his government to improve the accountability of public officials, which is going through Parliament.

"He has given this country a lifetime of public service, particularly for those fighting for justice," he added.

"His leadership took our party from one of its worst defeats to its best victories and created a platform to change this country for the better. We will use it well, and we wish his family the very best for the future."

Announcing his resignation, Sir Keir told the Camden New Journal it had been a "huge honour and privilege" to represent the London constituency for 11 years, ending weeks of speculation about whether he would remain an MP.

He added he was ready to "pass the baton to a successor", telling the newspaper it was the "right time" for him to leave Parliament.

He said: "I will now focus on other things and that will be international affairs including defence, security, trade and technology in a fast-changing world.

"I will also continue, as I have done for a long time now with others, to 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. So international affairs on the one hand, and continuing my work on violence against women and girls on the other."

Sir Keir became prime minister after winning a landslide majority at the 2024 election, but quit No 10 after pressure from Labour MPs to stand aside.

Conservative leader Kemi Badenoch wished Sir Keir the best for the future adding: "I can understand why he would not want to spend time with the Labour MPs who treated him so badly after he won them their seats."

Tory Party chairman Kevin Hollinrake accused Sir Keir of making "another U-turn having pledged to stay on", prompting a "costly by-election for taxpayers".

A date will not be set for the by-election until Sir Keir formally resigns his Commons seat.

This will only be confirmed once the government has given him a crown appointment, the mechanism that disqualifies him from being an MP.

Labour expects to select a candidate for the by-election by 9 September, according to the party's website.

Holborn and St Pancras has long been a Labour stronghold, with Sir Keir securing a more than 11,000-vote majority at the last general election in 2024.

Labour's main challenger in the seat is likely to be the Greens, who came second by vote totals at this year's local elections in wards that make up the constituency - with 29.8% of the vote to Labour's 39.5%.

Reform UK came a distant third by these vote totals, and the Greens' share was higher if they are given the votes in two wards where they stood aside.

Candidates for the by-election will not be confirmed until a later stage, but the Greens hinted that leader Zack Polanski was considering a run at the seat.

A spokesperson for the party said Polanksi, currently a member of the London Assembly, had "always made it clear he would like to be a London MP".

While it is unclear exactly what type of international affairs role Sir Keir may take up, global issues and diplomacy dominated his time as PM.

In his departure interview in July, Sir Keir was asked if he had another big political or international job in him, to which he replied: "I don't know is the honest answer to that."

By standing down so soon after quitting as PM, Sir Keir has departed from recent precedent for those in Downing Street before him.

Rishi Sunak is still the Tory MP for Richmond and Northallerton two years after leaving No 10, and his precedessor Liz Truss stayed on as a backbencher until she lost her seat to Labour at the 2024 election.

Theresa May stayed on as MP for five years after leaving Downing Street.

However, both Boris Johnson and David Cameron quit the Commons shortly afterwards.