Prime Minister Keir Starmer said on Monday he would resign, with a new leader to be in place by the time parliament returns in September, paving the way for Britan to have its seventh leader in 10 years. Less than two years after he won a landslide election victory that promised to end chaos in British politics, Starmer said it was clear that his party wanted him to go.

He said nominations for anyone to replace him would open on July 9. However his rival Andy Burnham is the clear frontrunner.

"The question my party is asking now is whether I am best placed to lead us into the next general election, I have heard the answer of my parliamentary party to that question, and I accept that answer with good grace," he said.

Starmer is the sixth prime minister in a decade to stand outside 10 Downing Street and announce a premature departure. It comes the day before Britain marks the 10th anniversary of its vote to leave the European Union, a decision that still roils the country's economy and politics.

He has struggled to deliver promised economic growth, repair tattered public services and ease the cost of living, and has been hamstrung by repeated missteps, including his decision to appoint Peter Mandelson, a scandal-tarnished friend of Jeffrey Epstein, as the UK ambassador to the United States.

Labour is losing liberal voters to the growing Green Party and facing a rising Reform UK, the Nigel Farage -led anti-immigration party that consistently leads in nationwide opinion polls.

US President Donald Trump weighed in even before an announcement, linking Starmer's potential exit to two of his recurring bugbears: immigration and renewable energy.

"Keir Starmer will resign as Prime Minister of The United Kingdom. He failed badly on two very important subjects- IMMIGRATION AND ENERGY (OPEN NORTH SEA OIL!). I wish him well! President DJT," Trump posted on his social media platform.

It was unclear whether Trump was responding to media reports about Starmer's plans. The two leaders didn't speak over the weekend.

Starmer's initially warm relationship with the president has soured in recent months over issues including the Iran war, which the UK didn't join.

In contrast to missteps on the domestic front, Starmer has won praise for his international role, notably in rallying European support for Ukraine in its fight against Russia's invasion, and working to mitigate the economic and political turmoil unleashed by the Iran conflict.

While many Labour lawmakers have rallied behind Burnham, some have said that Starmer had been treated unfairly. London legislator Neil Coyle railed on X against "the prospect of an utter stitch-up & the media circus being rewarded.

"When the next leader cannot change Trump, Iran, Ukraine, Putin, Musk, broadcast editorial & algorithm bias overnight they'll bay for his blood too. Better keep that guillotine sharp," he wrote.

Pressure had been building for months

The threat to Starmer, which had been building for months, increased sharply on Friday when Burnham, the Greater Manchester mayor, decisively won a parliamentary election to return to Westminster, beating a candidate from Nigel Farage's Reform UK party, which has led national opinion polls for more than a year.

That victory gave hope to Labour lawmakers that Burnham, a career politician known for his communication skills, could transform the fortunes of a party that has lost support under Starmer, whose popularity ratings have sunk to the lowest for any British leader.

Starmer thanked his colleagues for their support, his voice cracking with emotion as he also paid tribute to his wife and children.

The pound and British government bonds were steady in the immediate aftermath of Starmer's announcement, which investors had widely expected.

Despite the attempt at a smooth handover, the change is not without risk. Beyond saying that the country needs fundamental change and to bring down the cost of living, Burnham has yet to make clear his approach to foreign affairs, the economy and defence. Like Starmer, he could find he has little room to manoeuvre, hemmed in by bond market investors opposed to any additional borrowing, and confronted by an angry electorate which believes the country is not working properly. Britain already has the highest borrowing costs in the Group of Seven wealthy nations due to its high debt and interest payments, years of anaemic economic growth, its struggles to cut spending and the need to invest in areas like defence.

Investors spoken to by Reuters were divided over whether Burnham, who said last September that Britain had to get "beyond this thing of being in hock to the bond markets" would respect the need to reassure markets.

He has since said he was misrepresented.

"In our view, a Burnham premiership would inherit a precarious fiscal situation with few tools to deliver meaningful change," economists at Citibank said on Friday.

Starmer had pledged to fight any challenge

Starmer had said on Friday he would stand in any formal Labour leadership contest that sought to replace him. But that appeared to change over the weekend.

Whoever replaces Starmer will become Britain's seventh prime minister since the Brexit vote to leave the European Union which took place 10 years ago this week. That level of turnover - the highest in Britain in nearly two centuries - underlines the struggle of maintaining the support of voters angry at successive failures to improve living standards, public services and tackle illegal immigration. The political advisory group Eurasia had said the best outcome could be for Starmer to say he will step down in September, enabling him to attend a UK-European Union reset summit in July and give Burnham time to prepare for government.