Britain said Russia's withdrawal from the only regional capital in Ukraine that it had captured since its invasion began in February was another humiliation for its army but Moscow continued to pose a threat.
"Russia's announced withdrawal from Kherson marks another strategic failure for them," British defence minister Ben Wallace said in a statement on Saturday.
"In February, Russia failed to take any of its major objectives except Kherson. Now with that also being surrendered, ordinary people of Russia must surely ask themselves 'What was it all for?'," Wallace said.
Russia's withdrawal on Friday marked its third major retreat of the war and the first to involve relinquishing such a large city.
Wallace said Russia's army had suffered a huge loss of life in exchange for international isolationism and humiliation and Ukraine would press on with support from Britain and the international community.
"And while the withdrawal is welcome, no one is going to underestimate the continuing threat posed by the Russian Federation," he concluded.
(Reporting by William Schomberg; Editing by Christina Fincher)