British Prime Minister Keir Starmer and Ukrainian President Volodymyr Zelensky pose for a photo at 10 Downing Street in London, on Saturday. EPA-EFE/CHRIS J. RATCLIFFE / POOL

British Prime Minister Keir Starmer is hosting a summit of world leaders in London on Sunday, just two days after a lengthy and bad-tempered verbal exchange between Ukrainian President Volodymyr Zelensky and US President Donald Trump at the White House risked ending continued US military support for Ukraine.

Starmer, who welcomed Zelensky to Downing Street on Saturday, told the BBC on Sunday that the UK had agreed to work with Ukraine, France and “possibly one or two others” on “a plan to stop the fighting” in Ukraine, which they would then discuss with Washington.

As they sat down for talks on Saturday, Starmer assured Zelensky that the UK would “stand with Ukraine for as long as it takes”, added that Ukraine enjoyed the “full backing” of the UK and reiterated the British government’s support for a “lasting peace for Ukraine based on sovereignty and security”.

Zelensky and Starmer also signed a €2.7 billion loan for Ukrainian military supplies on Saturday, which is being funded by the interest earned on some €289 billion of frozen Russian assets, the Ukrainian Finance Ministry announced on Saturday evening.

Starmer is expected to welcome Italian Prime Minister Georgia Meloni, French President Emmanuel Macron, German Chancellor Olaf Scholz and Canadian Prime Minister Justin Trudeau to Lancaster House on Sunday, as well as the leaders of another 10 European countries, NATO Secretary General Mark Rutte, European Commission President Ursula Von der Leyen and European Council President Antonio Costa.

Zelensky, who lauded the “meaningful and warm” meeting with Starmer on Saturday and thanked the UK government and the British people for their “tremendous support”, is also due to meet King Charles before the summit begins on Sunday afternoon.