Russia has announced sanctions against 39 British politicians, business leaders, and journalists, barring them from entering Russia.
The list includes opposition Labour Party leader Keir Starmer, former Prime Minister David Cameron, TV journalist Piers Morgan, and BBC News presenter Huw Edwards.
London has been one of Kyiv's most vocal supporters since Russia's full-scale unprovoked invasion of Ukraine on February 24.
Russia's Foreign Ministry said the Britons listed "contribute to the hostile course of London aimed at the demonization of our country and its international isolation."
The names will be added to a list of more than 200 other Britons whom Russia has already banned, including most of Britain's leading politicians.
The travel bans are largely symbolic given the poor state of relations, but Russia's Foreign Ministry said it would keep adding to the list.
"Given London's destructive drive to spin the sanctions flywheel on far-fetched and absurd pretexts, work on expanding the Russian stop-list will continue," it said in a statement.
Separately, the Russian Prosecutor-General's Office said it had declared the nonprofit Calvert 22 Foundation based in London an "undesirable organization."
"It has been established that its activity poses a threat to the foundations of the constitutional order and the security of the Russian Federation," the Prosecutor-General’s Office said in a statement.
The organization, which was founded in 2009 by Russian-born economist Nonna Materkova, focuses on arts and culture in Russia and Eastern Europe.
The "undesirable organization" tag allows Russian authorities to ban their work in the country. It also carries the risk of fines or prison time for Russians working with the organizations.