Sir Keir Starmer has said he is “ready and willing” to put UK troops on the ground in Ukraine to help guarantee its security as part of a peace deal.
Writing in the Daily Telegraph, the UK prime minister said securing a lasting peace in Ukraine “is essential if we are to deter Putin from further aggression in the future”.
Ahead of an emergency summit with European leaders in Paris on Monday, Sir Keir said the UK was prepared to contribute to security guarantees to Ukraine by “putting our own troops on the ground if necessary”.
“I do not say that lightly,” he wrote. “I feel very deeply the responsibility that comes with potentially putting British servicemen and women in harm’s way.”
The prime minister added: “But any role in helping to guarantee Ukraine’s security is helping to guarantee the security of our continent, and the security of this country.”
The end of Russia’s war with Ukraine “when it comes, cannot merely become a temporary pause before Putin attacks again”, Sir Keir said.
UK troops could be deployed alongside soldiers from other European nations alongside the border between Ukrainian-held and Russian-held territory.
Sir Keir’s announcement comes after the former head of the Army, Lord Dannatt, told the BBC the UK military is “so run down” it could not lead any future peacekeeping mission in Ukraine.
The PM has previously only hinted that British troops could be involved in safeguarding Ukraine after a ceasefire.
He is due to visit President Donald Trump in Washington later this month and said a “US security guarantee is essential for a lasting peace, because only the US can deter Putin from attacking again”.
Sir Keir is meeting with other European leaders in response to concerns the US is moving ahead with Russia on peace talks that will lock out the continent.
US Secretary of State Marco Rubio plans to meet Russian officials in Saudi Arabia in the coming days for talks aimed at ending the war in Ukraine, US officials say.
On Saturday, US special envoy to Ukraine, Keith Kellogg, said European leaders would be consulted only and not take part in any talks between the US and Russia.
A senior Ukrainian government source told the BBC on Sunday that Kyiv has not been invited to talks between the US and Russia aimed at ending the war in Ukraine.
Trump earlier this week announced he had had a lengthy conversation with Russian President Vladimir Putin, and that negotiations to stop the “ridiculous war” in Ukraine would begin “immediately”.
Trump then “informed” Zelensky of his plan.
Writing in the Telegraph, Sir Keir said “peace cannot come at any cost” and “Ukraine must be at the table in these negotiations, because anything less would accept Putin’s position that Ukraine is not a real nation”.
“We cannot have another situation like Afghanistan, where the US negotiated directly with the Taliban and cut out the Afghan government,” he added.
“I feel sure that President Trump will want to avoid this too.”