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France’s President Emmanuel Macron, Britain’s Prime Minister Keir Starmer and Ukraine’s President Volodymyr Zelensky at a summit in London on the Ukraine warCHRISTOPHE ENA/AFP/Getty Images

Leaders from more than a dozen countries including Canada have agreed at a summit in London to create a “coalition of the willing” to provide a security guarantee for a peace deal to end the war in Ukraine.

British Prime Minister Keir Starmer convened the one-day summit on Sunday. It involved leaders from NATO, the European Union and 16 countries including Ukraine President Volodymyr Zelensky, Prime Minister Justin Trudeau and French President Emmanuel Macron.

Mr. Starmer said the leaders agreed to keep military aid flowing to Ukraine and that any lasting peace agreement must ensure Ukraine’s security. He also said Ukraine must be a participant in peace negotiations and that once a deal is reached, western nations should boost Ukraine’s defence capabilities to ensure it can fend off any future Russian aggression.

“We will go further and develop a coalition of the willing to defend a deal in Ukraine and to guarantee the peace,” he said during a press conference after the summit. “Not every nation will feel able to contribute, but that can’t mean that we sit back. Instead, those willing will intensify planning now with real urgency.”

Mr. Starmer said Britain has agreed to contribute troops along with a number of other countries including France.

The aim of Sunday’s summit was to demonstrate a united front for Ukraine, both militarily and diplomatically. All the leaders also went out their way to show their support for Mr. Zelensky in the wake of his tumultuous meeting with U.S. President Donald Trump on Friday. The Ukrainian President also met King Charles at the private Royal estate in Sandringham in a further demonstration of European resolve.

Mr. Trump has wavered on whether he believes a peace agreement is possible and he has insisted that Europe, and not the U.S., should provide any security guarantee. He has also been highly critical of Mr. Zelensky and far more positive about Russian President Vladimir Putin’s interest in stopping the fighting. On Friday the meeting at the White House attended by Mr. Zelensky descended into a shouting match between him, Mr. Trump and U.S. Vice President J.D. Vance broadcast live in front of the world media.

Mr. Trump’s pro-Kremlin position has unnerved European leaders. Sunday’s meeting was an attempt to mollify Mr. Trump by demonstrating that European countries have a role to play in any peace talks and that they will provide a backstop. Although Sunday’s London summit was planned before the White House debacle on Friday, it has taken on a new urgency.

Mr. Starmer said Britain and France will lead a European effort to come up with a more specific plan which will be presented to Mr. Trump. He said that he spoke to the U.S. President on Saturday about the proposal and he insisted that Mr. Trump was a reliable ally.

“I’m not going to go through the details of that conversation, but I would not be taking this step down this road if I didn’t think it was something that would yield a positive outcome in terms of ensuring that we move together – Ukraine, Europe, the UK and the US – together towards a lasting peace,” Mr. Starmer said Sunday.

Several countries have also announced plans to boost defense spending. Last week Mr. Starmer plans to increase its military spending from 2.3 per cent of gross domestic product to 2.5 per cent by 2027 and to 3 per cent within the next decade. On Sunday, Mr. Starmer announced a £1.6 billion financial package for Ukraine that will allow Kyiv to buy more than 5000 air missiles.

“We all have understood that after a long time of under investment, it is now of utmost importance to step up the defense investment for a prolonged period of time,” said European Commission president Ursula von der Leyen. In a message to Mr. Trump, she added; “we are ready, together with you, to defend democracy and the principle that there is a rule of law, that you cannot invade and bully your neighbour or change borders with force.”

On the street outside Lancaster House where the summit took place, Zak Herych, a Ukrainian-Canadian, stood with his girlfriend Sofiia Vystoropska who fled the Ukrainian city of Sumy shortly after Russia’s full-scale invasion. They were both draped in Ukrainian flags and came with several dozen others to show their support for Mr. Zelensky and their homeland.

“This has been a really hard time and Ukraine needs more support. Ukraine needs more support from the western world,” Mr. Herych said. He didn’t want to talk about Mr. Zelensky’s dust up with Mr. Trump, but said; “Americans need to get back to their senses with regards to the reality.”

Ms. Vystoropska has lost several friends in the war and she holds out hope that a peace agreement can be reached, but only if Ukraine’s security is ensured. “It’s a really stressful time now,” she said. “We don’t want just to have this peace and then fight Russia and when they decide to go to Poland or somewhere else.”