British armed forces have intercepted a Russian shadow fleet oil tanker in the English Channel during the early hours of Sunday morning, the prime minister has said.

In an operation lasting six hours, Royal Marine Commandos, alongside specialist officers from the National Crime Agency, intercepted the oil tanker in the Channel.

The operation marks the first time a Russian shadow fleet vessel has been interdicted in British waters, after Starmer agreed in March that UK troops and law enforcement officers should be able to board them.

The Ministry of Defence (MoD) said the UK has sanctioned more than 500 vessels.

It involved two Royal Navy ships, HMS Sutherland and HMS Ledbury, and aircrafts including Chinooks, Merlin Mk4 and Wildcat helicopters.

The tanker, Smyrtos, will be held and monitored off the south coast where it will be monitored for environmental and safety concerns.

Writing on social media platform X, Starmer said the operation “delivers yet another blow to Russia and reminds those fuelling Putin’s war in Ukraine that we will not let them hide”.

He said:  “I want to thank those involved, including our Armed Forces and law enforcement officers who keep this country safe 24 hours a day, 365 days a year.”

Conservative leader Kemi Badenoch also backed the armed force’s interception of the tanker.

She wrote on X: “I pay tribute to the brave Royal Marine Commandos who boarded a Russian shadow fleet oil tanker overnight in the English Channel.

“Russia’s illegal war in Ukraine is funded by their oil exports in defiance of sanctions.

“As Leader of the Opposition, I support the Government in standing with Ukraine.”

Russian sanctions

The MoD said the enforcement action was carried out against the vessel in UK territorial waters, in accordance with both domestic and international law.

The shadow fleet of more than 700 vessels is responsible for carrying roughly 75 per cent of Russia’s sanctioned oil, enabling the Kremlin to generate a war fund.

Attorney General Lord Richard Hermer wrote on LinkedIn: “This Government made clear that we would pursue Russia’s shadow fleet under the full force of international law.

“Russia relies on their shadow fleet tankers to fund their conflict in Ukraine, and this expertly delivered interdiction strikes another blow at Putin’s war machine.

The UK has already sanctioned more than 500 vessels, with Russia’s oil and gas revenue tumbling 24 per cent year on year in 2025.

Defence Secretary Dan Jarvis, who took up the position on Thursday night, said: “Operations like this require skill, professionalism and courage. I pay tribute to our armed forces personnel and all those involved.

“Russia relies on its shadow fleet to fund their conflict in Ukraine and our interdiction delivers a blow to Putin’s illegal war.”