Chelsea owner Roman Abramovich has been sanctioned by the UK government.
The Russian oligarch has been targeted due to his links to Russian President Valdimir Putin.
Abramovich - who has owned the London club since 2003 - has been actively seeking to sell Chelsea since the invasion of Ukraine by his home country.
However, following sanctions imposed by the UK government this morning, the club will no longer be able to be put up for sale.
His assets have been frozen, but the club has been given a special licence to allow its football operations continue.
But the implications will be wide-ranging on a day-to-day basis for the club.
Only season ticket holders will be allowed to attend matches, while no merchandise sales will be permitted.
No transfers or new contracts will be permitted either as the sanctions remain in place.
"There can be no safe havens for those who have supported Putin’s vicious assault on Ukraine," British Prime Minster Boris Johnson said.
"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."
Abramovich is one of a number of oligarchs targeted by the UK government in this round of sanctions.
Industrialist Oleg Deripaska, worth £2 billion, and Rosneft CEO Igor Sechin are among the other to have been hit.
Britain's Foreign Secretary, Liz Truss, added:
"Today’s sanctions show once again that oligarchs and kleptocrats have no place in our economy or society.
"With their close links to Putin they are complicit in his aggression.
"The blood of the Ukrainian people is on their hands. They should hang their heads in shame.
"Our support for Ukraine will not waver.
"We will not stop in this mission to ramp up the pressure on the Putin regime and choke off funds to his brutal war machine."
