Britain is targeting Russia's largest oil companies and the country's "shadow fleet" of oil tankers in a bid to cut off Vladimir Putin's ability to fund the war in Ukraine.
The UK government is also pursuing a major Indian oil refinery and four Chinese oil terminals in a package of 90 new sanctions.
Chancellor Rachel Reeves said the move was expected to have a significant impact on Russia's economy and its ability to sustain military operations in Ukraine.
"We are sending a clear signal: Russian oil is off the market," she said ahead of a meeting in Washington DC with global counterparts to discuss Russian sanctions.
The announcement comes as the G7, a grouping of some of the world's most advanced economies, prepares to consider a plan to effectively seize hundreds of billions from the proceeds of Russian investments, frozen since the invasion of Ukraine. A vast bulk of Russia's assets are held as cash at the European Central Bank, after its underlying bond investments matured.
The European Union (EU), where the bulk of funds are held, had been reluctant to pursue the wider plan, but appears to be developing a way round legal concerns. It will be considered at an EU summit next week.
Ukraine has significant funding needs as the war continues, both in arms and reconstruction.
Earlier this year, the UK joined the US in directly sanctioning energy companies Gazprom Neft and Surgutneftegas.
At the time the then Foreign Secretary, David Lammy, had said it would "drain Russia's war chest – and every ruble we take from Putin's hands helps save Ukrainian lives".
The US separately has discussed putting additional tariffs on goods from China, up to 500%, tied to Beijing's purchases of Russian oil.
But Treasury Secretary Scott Bessent said on Wednesday that the US would not take that step unless Europe agreed to do something similar.
"We will respond if our European partners will join us," he said.
