Sir Keir Starmer has pledged to put Ukraine in the "strongest possible position" in a trip to Kyiv where he signed a "landmark" 100-year pact with the war-stricken country.
The prime minister's visit on Thursday was at one point marked by loud blasts and air raid sirens after a Russian drone attack was intercepted by Ukraine's defence systems.
Acknowledging the "hello" from Russia, Volodymyr Zelensky said Ukraine would send its own "hello back".
The Ukrainian president praised the UK's commitment against the backdrop of concern that US President-elect Donald Trump could potentially reduce aid.
