The United States and Britain would seek to cut off Russian companies' access to U.S. dollars and British pounds if Russia attacks Ukraine, British Prime Minister Boris Johnson warned on February 20.
"The plan that we are seeing is for something that could be really the biggest war in Europe since 1945 just in terms of sheer scale," Johnson told the BBC.
Johnson said that, in the event of an invasion, the West would bring in even more far-reaching sanctions against Russia than have been suggested before.
Johnson said, Britain and the United States would stop Russian companies "trading in pounds and dollars," a move that he said would "hit very, very hard" with its impact.
SEE ALSO: Ukraine Live Briefing: Moscow, Kyiv Trade Air StrikesRussia is one of the world's top exporters of oil, gas, and metals - which are largely priced and settled in U.S. dollars. Therefore, blocking Russian companies from access to dollar markets could have a stinging impact.
Previous sanctions suggested by British ministers include broadening the range of Russian people and businesses the United Kingdom could target.
Johnson has said his government would target Russian banks and Russian companies. Britain has not spelled out who would fall under the sanctions, but has pledged that there would be nowhere for Russian oligarchs to hide.
SEE ALSO: Zelenskiy Says Ukraine Will Defend Itself With Or Without Partners Amid Soaring Tensions With RussiaHundreds of billions of dollars have flowed into London and Britain's overseas territories from Russia since the fall of the Soviet Union in 1991. London has become the Western city of choice for the super-wealthy of Russia and other former Soviet republics.
Western leaders have warned in recent weeks that Russia -- which has deployed more than 150,000 troops on the Ukrainian border -- could be preparing to attack at any time. But Moscow has denied the claims, saying troops are conducting military exercises in the region.