Sir Keir Starmer has suggested a coalition of European allies could step up and defend a potential deal for Ukraine to “guarantee the peace”.

The prime minister indicated some EU nations could be prepared to increase defence spending to protect any peace deal that is agreed between Ukraine and Russia.

But speaking at summit of EU leaders in central London, Sir Keir acknowledged that no such coalition had yet been formed and that “not every nation will feel able to contribute”.

Instead, he said “those willing” – though he did not state which countries this included – would “intensify planning now with real urgency”.

In a sign this could mean troops from member states being sent to Ukraine, he added: “The UK is prepared to back this with boots on the ground and planes in the air, together with others. Europe must do the heavy lifting.”

The UK, France and Ukraine will work on a ceasefire plan to present to the United States, the prime minister has said, in the wake of Volodymyr Zelenskyy’s White House clash with Donald Trump.

Sir Keir Starmer, who visited Washington on Thursday, said he believes Mr Trump does want a “lasting peace” between Russia and Ukraine.

He also said Europe is in a “moment of real fragility” and he would not trust the word of Vladimir Putin.

Follow live – UK hoping Ukraine peace plan can get ‘back on track’ at London summit

Referring to the argument in the White House’s Oval Office on Thursday between Mr Trump, US vice president JD Vance and Ukrainian president Mr Zelenskyy, the PM said it made him feel “uncomfortable”.

“Nobody wants to see that,” he told the BBC’s Sunday with Laura Kuenssberg.

He added: “We have to find a way that we can all work together. Because, in the end, we’ve had three years of bloody conflict. Now, we need to get to that lasting peace.”

The prime minister said he was in his office when the White House shouting match began to be broadcast.

“Clearly, you know, there’s a lot of tension,” he said. “The cameras were on.”

Later in the evening he phoned both Mr Trump and Mr Zelenskyy, saying his “driving purpose” is to “bridge this and get us back to the central focus”.

On Saturday, the PM said he had “quite a long time with President Zelenskyy” before speaking to Donald Trump and French president Emmanuel Macron on the phone.

“We’ve now agreed that the United Kingdom, along with France and possibly one or two others, will work with Ukraine on a plan to stop the fighting, and then we’ll discuss that plan with the United States,” he said.

Of Mr Trump, he said: “I am clear in my mind that he does want a lasting peace.”

Asked why that was, he said: “Because I’ve spoken to him a number of times. I’ve got to know him. I’ve had extensive discussions with him and I believe his motivation is lasting peace.”

He added: “If the central question you’re putting to me is do I trust Donald Trump when he says he wants lasting peace? The answer to that question is yes.”

The PM said he was still pushing for a US “backstop” on Ukrainian security, adding that it was the subject of “intense” discussion.

The “components of a lasting peace”, he said, include a “strong Ukraine to fight on, if necessary, to be in a position of strength”.

And he is pursuing a “European element to security guarantees”.

“That’s why I’ve been forward-leaning on this about what we would do – and a US backstop,” he said.

“That’s the package: all three parts need to be in place, and that’s what I’m working hard to bring together.”

Asked if he would trust Vladimir Putin, Sir Keir said: “Well, no, I wouldn’t trust Putin, which is why I want a security guarantee.

“I wouldn’t trust him not to come again, because he’s proven that he will come again. He’s already done it and we know what his ambitions are.”

Sir Ed Davey, leader of the Liberal Democrats, said his party would support sending British troops to Ukraine as peacekeepers in the event that a “credible” deal is struck.

Conservative leader Kemi Badenoch said European nations need to “make sure that America does not disengage”, adding: “If we all get dragged into an escalation, America will get dragged into it eventually.”

She described Volodymyr Zelenslyy as a “hero” and said her heart “went out to” him during the on-camera argument at the White House.

“I watched it and I couldn’t believe what was happening,” she said. “He was being humiliated.”

Such “difficult conversations” should not happen in front of the cameras, she added.

Read more from Sky News:
Trump-Zelenskyy clash: Sky News correspondents’ views
Singer from New York Dolls dies aged 75
Pope’s condition is slightly improved

The UK is holding an international defence summit on Sunday, hosting the leaders of Italy, France, Germany, Denmark, Norway, Poland, Canada, Finland and Romania.

Italian Prime Minister Giorgia Meloni told Sir Keir Starmer it is “very, very important that we avoid the risk that the West divides” as she arrived for talks at Number 10.

EU Commission president Ursula von der Leyen, NATO secretary general Mark Rutte, and Turkey’s foreign minister Hakan Fidan will also attend the summit.

It is hoped the meeting will help to get things “back on track”, a government source has told Sky News.

However, they admitted there will be “more ups and downs” ahead.

“We must keep our eyes on the prize.”

The insider added that the government was “working yesterday to get [Volodymyr] Zelenskyy back to the table” and finish the minerals deal with the US.

That was thrown into question on Friday during the clash at the White House.

The source said: “We think it’s the right thing to do. Today is about getting European leaders to go beyond the Twitter rhetoric and step up on defence spending – prepare now for a world with no US security guarantee for Europe, not just in Ukraine.”

Volodymyr Zelenskyy has said the Ukrainian people “are truly thankful” for US support, hours after talks with Donald Trump descended into a row at the White House.

During a disastrous meeting with Mr Trump, the Ukrainian president was asked by vice president JD Vance, “have you said thank you once?”

In a lengthy social media post, Mr Zelenskyy said: “I always begin with words of gratitude from our nation to the American nation”.

The Ukrainian president insisted the US-Ukraine relationship “is more than just two leaders” but it was “crucial” for his country to have Mr Trump’s support.

He added: “American people helped save our people. Humans and human rights come first. We’re truly thankful. We want only strong relations with America, and I really hope we will have them.”

Ukraine latest: Zelenskyy says Ukraine should be ‘not forgotten’

Mr Zelenskyy will meet Sir Keir Starmer in Downing Street on Saturday afternoon after his plane landed at Stansted Airport.

It comes ahead of a major summit hosted by the UK prime minister on Sunday, where more than a dozen European and EU leaders including Mr Zelenskyy will meet to discuss the Ukraine war and security.

The Ukrainian president had travelled to Washington DC to attempt to secure a ceasefire agreement after three years of war with Russia and a possible mineral deal with the US.

The meeting descended into a shouting match in front of cameras and journalists.

Mr Vance told Mr Zelenskyy: “I think it’s disrespectful for you to come to the Oval Office to try to litigate this in front of the American media.

“You should be thanking the President [Trump] for trying to bring an end to this conflict.”

‘You’re gambling with World War Three’

The Ukrainian president tried to object but Mr Trump spoke over him and told him: “You’re gambling with the lives of millions of people.

“You’re gambling with World War Three, and what you’re doing is very disrespectful to the country, this country that’s backed you far more than a lot of people say they should have.”

Mr Zelenskyy defended himself and his country, openly challenging Mr Trump on his softer approach to Vladimir Putin and urging him to make “no compromises with a killer”.

More from Sky News:
How Starmer secured wins at the White House
Inside the Oval Office with Trump and Starmer

European leaders express support for Zelenskyy

After the row, Mr Trump told his Ukrainian counterpart to leave the White House, according to a US official, leaving the minerals deal in limbo.

European leaders expressed their support for Mr Zelenskyy ahead of the UK summit on Sunday.

France’s Emmanuel Macron, Germany’s Olaf Scholz, and Poland’s Donald Tusk all shared social media posts expressing their support.