Sir Keir Starmer has issued a statement of support as Ukraine marks 33 years since it declared independence from the Soviet Union.
The prime minister told Ukrainians the UK will back them “today and always”, offering a “crystal clear” message of solidarity to the war-torn nation.
Ukraine’s supreme soviet agreed the state should leave the Moscow-based Soviet Union on 24 August 1991, a decision backed by Ukrainian voters at a referendum in December that same year.
Sir Keir said: “My message to all Ukrainians, whether on the front line or here in your second home in the UK, is crystal clear: we are with you today and always.
“That is what I told President Zelensky when he sat at our Cabinet table and where, on behalf of the British people, I outlined that it is not just the British government that’s behind Ukraine – it’s all of us. We are with you for as long as it takes.”
“Slava Ukraini,” he added, a national salute in the country which translates to glory to Ukraine.
The anniversary comes just days after President Volodymyr Zelensky suggested that the UK’s support for Ukraine was weakening.
While he acknowledged that Britain’s leadership had saved thousands of lives since the start of the war, over the weekend he said support had recently “slowed down”.
But a Downing Street spokesperson said the prime minister remains “absolutely resolute in his support for Ukraine”.
The Ministry of Defence (MoD) on Saturday said the 33-year milestone has “now become an opportunity for people across the UK and the world to honour the strength, resilience and identity of the Ukrainian people”.
Thousands have died since Russia invaded on 24 February 2022. Ukrainian forces are currently advancing through Russia’s Kursk region, while Vladimir Putin’s forces are doing the same in eastern Ukraine.
The MoD has urged people to share videos of them clapping, cheering, playing music, singing or ringing bells on social media using the hashtag #MakeNoiseForUkraine on Saturday.
The government confirmed more than 45,000 Ukrainian recruits have received training on British soil since Russia invaded Ukraine in February 2022, as part of an international effort codenamed Operation Interflex.
Defence Secretary John Healey said: “On their Independence Day, we salute the fearless resolve of the Ukrainian people.
“They fight for freedoms that we must never take for granted.
“Ukraine has no firmer friend than the UK and we will stand with them for as long as it takes. Britain is united for Ukraine.”
Admiral Sir Tony Radakin, chief of defence staff, said: “I offer my admiration to the men and women of Ukraine’s Armed Forces for the heroic determination with which they defend their country.
“Their initiative, tenacity and skills are an example to the UK Armed Forces; and the clarity of their cause is an inspiration to freedom-loving peoples everywhere.”