Sir Keir Starmer will urge allies to step up economic efforts to “cripple” Vladimir Putin’s military amid European concerns about US President Donald Trump’s support for Ukraine.
The Prime Minister will discuss the situation with the so-called “coalition of the willing” on Friday.
The talks come after discussions between Volodymyr Zelensky and Mr Trump failed to result in the US supplying Tomahawk missiles and reports the Ukrainian president faced pressure to accept Moscow’s demands.
The Financial Times reported that last week’s meeting between Mr Zelensky and Mr Trump at the White House descended into a “shouting match”.
Mr Zelensky has publicly insisted the meeting was “positive” but suggested the US president did not want to upset the Russians before a face-to-face meeting with Mr Putin.
“In my opinion, he does not want an escalation with the Russians until he meets with them,” Mr Zelensky said.
Sir Keir said he wanted Ukraine to be put in the “strongest possible position” before, during and after any ceasefire – although he said Mr Putin was not serious about peace.
Before this week’s coalition of the willing talks, Sir Keir said: “We must be resolute in our support for Ukraine and I’m committed to intensifying our efforts to cripple Putin’s war machine.
“Russia’s stalling tactics have shown time and time again that Ukraine is the only party serious about peace. We can all see that Putin is not and he continues to choose violence and destruction.
“Tyrants like Putin only respond to strength. We must ramp up the pressure on his economy and defence industry, as we did last week with a major package of sanctions until he’s ready to make peace.
“As winter approaches we will continue to step up our support – humanitarian, financial and military – so Ukraine can defend its people and its sovereignty.
“We cannot lose sight of the fact that Ukraine’s future is our future, and the next few days and weeks will be pivotal for the future of European security.”
