Russia’s withdrawal from Kherson will bring “significant reputational damage”, according to British defence experts.
Russia finished withdrawing its troops from the city on Friday.
UK Defence Secretary Ben Wallace said Russia’s retreat marked “another strategic failure” and he pledged continued British support for Ukraine.
“The Russian army has suffered a huge loss of life as a result of their illegal invasion and have only achieved international isolationism and humiliation,” he said.
“Ukraine will press on.”
Intelligence analysts believe Moscow’s exit was likely to have begun as early as October 22, when Russian-installed figures urged civilians to leave. On Friday, Russian news agency Tass said as many as 115,000 civilians had left Kherson.
It is anticipated that Ukraine will now occupy large areas of the Kherson region on the western bank of the Dnipro River, with its forces largely in control of city.
Videos and pictures posted on social media later showed residents celebrating in the streets, with the Ukrainian flag flying over a central square.
An adviser to the Ukrainian defence minister claimed there is “panic” in Russian ranks, but cautioned the war is “far from over”.
Yuriy Sak told BBC Radio 4’s Today programme that Ukraine is feeling “quietly optimistic”.
Kherson was one of the first Ukrainian cities to be captured in the war Moscow waged on its neighbour from February 24.
The withdrawal, which was ordered during a Ukrainian counter-offensive, has drawn no comment from Russian President Vladimir Putin.
In an intelligence update posted on social media, the UK Ministry of Defence (MoD) said Moscow’s troops had “highly likely” destroyed road and rail bridges over the Dnipro River as part of their retreat.
“There is a realistic possibility that Russian military equipment and forces in civilian attire had been evacuating in conjunction with the 80,000 stated evacuated civilians in recent weeks,” they said.
The MoD said is it probable Moscow is still attempting to evacuate forces from other parts of the region across the river to defensible positions on the eastern bank.
“Kherson was the only regional capital city captured since February by Russian forces so the withdrawal brings significant reputational damage,” it said.