Russian billionaire Alisher Usmanov, who was sanctioned by Britain earlier this month, denies the government's claims he owns two multi-million-pound mansions in the country, his spokesman said.
The spokesman for Usmanov said on Tuesday that all his properties were transferred in 2006 into "irrevocable trusts", which normally cannot be amended after they are created.
Usmanov, who is believed to be worth more than $18 billion, first came to public prominence in Britain when he invested in Premier League soccer clubs, first with a 30% stake in Arsenal and then with a sponsorship deal at Everton that was suspended earlier this month.
Usmanov is one of several wealthy Russians sanctioned by Britain following Russia's Feb. 24 invasion of Ukraine, over what the British government says are links to Russian President Vladimir Putin.
Britain said on March 3 that Uzbekistan-born Usmanov - who has business interests in mining and telecoms - owned a mansion in London worth an estimated 48 million pounds ($64 million) and another vast estate southwest of London.
"All of Mr Usmanov's properties were settled into the irrevocable trusts long before the sanctions came," Usmanov's spokesman said. "It had nothing to do with sanctions and was determined by estate planning."
Usmanov, 68, was named in the Sunday Times Rich List last year as Britain's sixth richest person.
A spokesman for British Prime Minister Boris Johnson said he would not go into detail on individual cases, but was confident the sanctions would have a "significant impact" on Usmanov.
The government "have an enhanced capability when it comes to enforcing sanctions," he said. "The sanctions against Usmanov were enacted with immediate effect, he cannot access his assets."
Putin calls the war, the biggest attack on a European state since World War Two, a "special military operation" to disarm Ukraine and protect it from "Nazis". The West calls that a false pretext for an unprovoked war of aggression.
(Reporting by Andrew MacAskill, editing by William James, William Maclean)
