King Charles met Volodymyr Zelensky at Sandringham on Sunday in an overt show of solidarity with the Ukrainian president.
The meeting came after Donald Trump and the US vice-president JD Vance berated Mr Zelensky over his conduct during the Ukraine war and apparent lack of gratitude for American donations during a televised conference in the Oval Office.
Mr Zelensky had been in London to attend a summit of European leaders which saw them discuss a peace plan for Ukraine and security on the continent, a day after Sir Keir Starmer said Mr Zelensky had "full backing across the United Kingdom" as he welcomed him to Downing Street.
The decision to invite the Ukrainian president to Sandringham is the most conspicuous political act the King has made since succeeding Queen Elizabeth II, who went to great lengths to keep out of politics.
The gestures by both the King and the prime minister are bound to be seen as the clearest possible signal that Britain is backing Mr Zelensky after his bitter fall-out with Mr Trump.
The prime minister is attempting to bridge the gap between Ukraine and the White House, which was more evident than ever when Mr Trump accused Mr Zelensky of not being ready for peace in the heated White House show down.
Cabinet minister Nick Thomas-Symonds said it is “entirely appropriate” that Mr Zelensky met the King, rejecting suggestions that the move is a provocation to the White House.
The meeting comes just three days after Mr Trump accepted an invitation from the King for an unprecedented second state visit to Britain – delivered to him personally by Sir Keir.
“I think it's up to the White House how they see the diplomacy of the moment", Mr Thomas-Symonds told Sky News on Sunday morning.
“The prime minister is in regular contact with President Trump, but I think it is entirely right that there is a recognition given of the role President Zelensky has played in defending the sovereign nation of Ukraine over the past three years.
“So it's entirely appropriate he sees His Majesty the King.”
Speaking on Sunday, Sir Keir admitted the clash between Mr Zelensky and Mr Trump made him feel uncomfortable.
"Yes, I felt uncomfortable. Nobody wants to see that," he told the BBC's Sunday with Laura Kuenssberg.
"The important thing is how to react to that. There are a number of different routes people could go down. One is to ramp up the rhetoric as to how outraged we all are or not.
"The other is to do what I did, which is roll up my sleeves, pick up the phone, talk to President Trump, talk to President Zelensky, then invite President Zelensky for an extensive meeting yesterday, a warm welcome, and then further pick up the phone to President Macron and President Trump afterwards.
"Because my reaction was, we have to bridge this. 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.”
