British Prime Minister Rishi Sunak and Ukrainian President Volodymyr Zelenskyy held a phone conversation on Thursday, the British government said in a statement.
"The Prime Minister praised the bravery of the Ukrainian armed forces and reiterated the UK's unwavering military, economic and political support," according to the statement.
Zelenskyy set out how UK military support is protecting vital energy infrastructure and helping Ukrainian troops to make advances on the battlefield against Russia.
"Ahead of next week's G20 meeting, the leaders discussed the importance of continued coordinated international support for Ukraine. They agreed to remain in close contact to make progress on these issues and ensure Ukraine succeeds as a sovereign and democratic nation," according to the statement.