With UK forces having boarded for the first time a ship carrying sanctioned Russian oil, Syed Rahman of Rahman Ravelli details the reasons and legal basis for the action.
The boarding of the sanctioned Russian shadow fleet oil tanker Smyrtos in the Channel by British forces was the first time such action has been taken.
In a move that the UK government claimed was a blow to “Putin’s war chest’’, Royal Marine Commandos and National Crime Agency (NCA) officers boarded the ship, which was carrying Russian crude oil worth about USD 30 million to India. It was then held and monitored off the south coast as investigations continued.
This first-ever boarding of a shadow fleet vessel, which was undertaken in close collaboration with French authorities, came three months after then Prime Minister Keir Starmer agreed that British armed forces and law enforcement officers were able to board such ships, in accordance with international law. Notably, the UK government’s actions also followed the issuing of a general licence by the Office of Financial Sanctions Implementation (OFSI), permitting government authorities to interdict (i.e. to authoritatively block or prohibit) persons contravening sanctions laws.
Under the United Nations Convention on the Law of the Sea (UNCLOS) Article 110, a warship can exercise a right of visit to verify the flag where there are reasonable grounds to suspect the vessel is without nationality. If a vessel is determined to be stateless, the UK can exercise powers available under its domestic legislation; including the ship sanctions provisions in the Russia (Sanctions) (EU Exit) Regulations 2019, and the criminal and maritime enforcement powers contained in the Policing and Crime Act 2017. The Smyrtos had operated under the flag of Cameroon.
Attacking
The UK sees disrupting Russia’s 700-vessel shadow fleet as a major means of attacking the funding that supports the Russian aggression in Ukraine. The fleet carries 75% of Russia’s sanctioned oil, which provides the Russian government with a major source of revenue for its war effort. The UK has already sanctioned nearly 600 vessels. Russia’s oil and gas revenues fell by 24% year-on-year in 2025.
The actions taken were probably heavily driven by political grandstanding. The seizure followed the resignation of the Defence Secretary John Healey in protest at the underfunding of the Defence Investment Plan. And the three-day G7 Summit in France, where Russia sanctions were set to be a huge topic of discussion (and were), began the day after the seizure.
The seizure of such ships obviously has huge implications, both politically and economically. The current state of the world, with conflict in Ukraine resulting in sanctions on Russia and hostilities in the Middle East, means that the oil and gas markets are in turmoil. This is exemplified by the fact that the UK government, through OFSI, had previously issued general licences for the trade of sanctioned processed oil, meaning the trade of Russian crude oil processed in third countries was possible. It remains to be seen whether the turmoil caused by such action will be worth the positive effect it generates.
