Chelsea FC owner Roman Abramovich has been sanctioned by the UK government as part of its response to Russia's invasion of Ukraine.
He is one of seven oligarchs to be hit with fresh sanctions, including asset freezes and travel bans.
The list also includes billionaires Igor Sechin and Oleg Deripaska, both seen as allies of Vladimir Putin.
Prime Minister Boris Johnson said "there can be no safe havens" for those who have supported the invasion.
"Today's sanctions are the latest step in the UK's unwavering support for the Ukrainian people. We will be ruthless in pursuing those who enable the killing of civilians, destruction of hospitals and illegal occupation of sovereign allies," Mr Johnson said.