The MOD said the action was taken despite Russia’s efforts to evade sanctions and continue funding its war in Ukraine. The enforcement action took place in international waters and was carried out in accordance with domestic and international law.
The military operation lasted six hours. It was supported by aircraft from the Maritime Air Group, including Chinooks, Merlin Mk4 and Wildcat aircraft, as well as an RAF P-8 aircraft, HMS Sutherland and HMS Ledbury.
The Prime Minister agreed in March that British Armed Forces and law enforcement officers could board shadow fleet vessels in accordance with international law. The SMYRTOS will be provisionally moved to an anchorage off the south coast of England and monitored for environmental or safety concerns.
“This operation delivers yet another blow to Russia and reminds those fueling Putin’s war in Ukraine that they cannot hide,” Prime Minister Keir Starmer said. “I want to pay tribute to all those involved, including our Armed Forces and law enforcement officers who keep this country safe 24 hours a day, 365 days a year.”
“Operations like this require skill, professionalism and courage. I pay tribute to our Armed Forces personnel and all those involved,” Defence Secretary Dan Jarvis said.
“Russia relies on its shadow fleet to fund their conflict in Ukraine and our interdiction delivers a blow to Putin’s illegal war,” Jarvis said. The MOD said the operation builds on recent British support to allies involved in interdicting shadow fleet vessels.
That support included RAF and Royal Navy capabilities assisting US and French operations. The MOD said the SMYRTOS operation was conducted in close coordination with France.
The UK said disrupting the shadow fleet helps reduce the resources sustaining Russia’s aggression in Ukraine. It also said the action limits Russia’s capacity to threaten security across Europe and beyond.
The MOD said the shadow fleet is responsible for carrying 75% of Russia’s sanctioned oil. It said the fleet includes more than 700 vessels and provides a critical lifeline for the Kremlin.
The UK has already sanctioned almost 600 Russian shadow fleet vessels. The government said sanctions are having an effect, with Russian oil and gas revenues falling by 24% year-on-year in 2025.
The MOD said Russia’s oil revenues are down 27% compared with October 2024, reaching their lowest level since the start of the war. In the first quarter of 2025, ships sanctioned by the UK carried $1.6 billion less in Russian oil than a year earlier.
The government said more than 72% of shadow tankers are over 15 years old. It also said there have been more than 50 incidents involving Russia’s shadow fleet.
The MOD said the operation sends a message that the UK will use available legal tools to enforce sanctions and protect security. It cited UNCLOS Article 110, which permits a warship to exercise a right of visit to verify a vessel’s flag where there are reasonable grounds to suspect it is without nationality.
Where a vessel is determined to be stateless, the UK can use powers available under domestic legislation. Potential domestic powers include ship sanctions provisions under the Russia (Sanctions) (EU Exit) Regulations 2019 and criminal and maritime enforcement powers under the Policing and Crime Act 2017.
