Sir Keir Starmer is heading to meet Donald Trump today as part of Ukrainian President Volodymyr Zelensky’s entourage of European leaders.
The Prime Minister will join France’s Emmanuel Macron, Germany’s Friedrich Merz, Italy’s Giorgia Meloni and Finland’s Alexander Stubb in the White House.
NATO chief Mark Rutte and European Commission boss Ursula von der Leyen are also travelling to Washington DC to join the talks with Mr Trump and Mr Zelensky.
The US and Ukrainian presidents are set to hold an hour-long meeting before wider discussions between Mr Trump and European leaders.
They are expected to use those talks to urge Mr Trump not to cede to Vladimir Putin’s demands for Ukraine to surrender the whole of the Donbas region to Russia.
The European leaders are being dubbed Mr Zelensky’s ‘back-up’ following the Ukrainian President’s previous acrimonious visit to the White House.
In an astonishing spat in February, US vice-president JD Vance accused Mr Zelensky of not being thankful enough for American support in the face of Russia’s invasion.
The public row resulted in US aid to Ukraine being temporarily halted and sparked fresh panic across European capitals that Mr Trump was siding with the Kremlin.
Mr Zelensky and Mr Trump have since attempted to repair relations, including with talks in the Vatican on the sidelines of Pope Francis’s funeral in April.
But the US President infuriated Ukrainians by rolling out the red carpet for Mr Putin during their talks about a potential ceasefire in Alaska last week.
Mr Trump also ratcheted up tensions ahead of Monday’s talks by claiming Mr Zelensky ‘can end the war with Russia almost immediately, if he wants to’.
He also ruled out future NATO membership for Ukraine and said Crimea would not be returning from Russian annexation.
In a post on his Truth Social website, the US President wrote: ‘President Zelenskyy of Ukraine can end the war with Russia almost immediately, if he wants to, or he can continue to fight. Remember how it started.
‘No getting back Obama given Crimea (12 years ago, without a shot being fired!), and NO GOING INTO NATO BY UKRAINE. Some things never change!!!’
In a follow-up post, Mr Trump said it was a ‘great honour’ to host a slew of European leaders in Washington.
‘Big day at the White House tomorrow. Never had so many European Leaders at one time. My great honor to host them!!! President DJT,’ he wrote.
Britain, France and Germany are said to have taken the lead on preparing Ukraine’s delegation for Monday’s meeting – including advice on how not to upset Mr Trump.
Sir Keir met with Mr Zelensky in Downing Street on Thursday ahead of Mr Trump’s talks with Mr Putin in Alaska.
The Prime Minister and Mr Macron, the French President, also co-chaired a virtual meeting of the so-called ‘coalition of the willing’ on Sunday.
Following the talks, Mr Macron said Ukraine’s allies would ‘present a united front’ to Mr Trump during Monday’s meeting in the White House.
‘If we are weak with Russia today, we’ll be preparing the conflicts of tomorrow and they will impact the Ukrainians and – make no mistake – they can impact us, too,’ he added.
Mr Zelensky is expected to face calls from Mr Trump to concede to full Russian control of Donetsk and Luhansk, two mineral-rich regions of Ukraine that are mostly occupied by Russia.
In exchange for these demands, Mr Puting would reportedly withdraw his forces from other areas of Ukraine and accept a NATO-like guarantee that Ukraine would be protected from further incursion.
European leaders have said it is up to Ukraine to decide how it wishes to end the war.
Mr Trump has appeared to drop his calls for a ceasefire after his summit with Mr Putin in Alaska.
The US President has instead said he wants to focus a long-term peace deal, although US secretary of state Marco Rubio has signalled a deal is ‘still a long ways off’.
There will be ‘additional consequences’ for Russia if it does not agree to a peace deal, Mr Rubio added, but he suggested fresh financial sanctions would be unlikely to force Mr Putin to the negotiating table.
Ms von der Leyen suggested at a press conference on Sunday that both a ceasefire and a peace deal would have the same impact: to ‘stop the killing’.
Appearing alongside her, Ukraine’s Mr Zelensky appeared to agree, though he also signalled his preference for a ceasefire.
‘It’s impossible to do this under the pressure of weapons. So it’s necessary to cease fire and work quickly on a final deal,’ he said.
Government minister Stephen Kinnock this morning said Mr Zelensky must not be forced to accept a peace deal if he is not happy with its terms.
He said Sir Keir had three objectives for when he meets Mr Trump at the White House alongside Mr Zelensky on Monday.
He told Times Radio: ‘The first of all is to make it absolutely clear that any decisions taken about Ukrainian territory must be taken with the agreement of the Ukrainian government and President Zelensky.
‘The other is that the pathway for Ukraine to NATO and to security guarantees cannot be dictated to them by any other country.
‘And the other is to send a very clear message that we the British people stand firmly shoulder-to-shoulder with the Ukrainian people as we showed when we opened our homes and our hearts to the Ukrainian refugees.’