STORY: Zelenskiy thanked Britain for its support "from the first days of the full-scale invasion."
"Thank you so much, we are proud, really, and have very good relations with Rishi," Zelenskiy said.
The meeting was short, with Sunak quickly arriving in parliament to attend the weekly prime minister's questions.
London was Zelenskiy's first stop on only his second trip abroad since Russia invaded Ukraine on Feb. 24 after a visit to the United States in December. He is due to travel onto Brussels on Thursday where the European Union is holding a summit.
Britain announced an immediate surge of military deliveries to Ukraine to help it fend off an intensifying Russian offensive and pledged to train its pilots .