In what marked a first for UK armed forces, British Royal Marines and officers from the National Crime Agency (NCA) boarded a Russian-linked oil tanker believed to be part of Moscow’s so-called “shadow fleet” during a major operation in the English Channel early on Sunday.
The vessel, the Smyrtos, has since been detained off England’s southern coast while investigators continue examining its activities, according to the Ministry of Defence (MoD).
During the operation, authorities arrested a 38-year-old Indian national suspected of breaching sanctions imposed under UK regulations targeting Russia. He remains in custody.
The NCA said the ship’s remaining 24 crew members, who are citizens of Georgia and India, are cooperating with investigators. A video released by the MoD showed commandos descending from a helicopter onto the tanker before conducting searches throughout the vessel. Additional footage captured NCA officers reviewing documents and inspecting ship records.
According to British authorities, Russia’s “shadow fleet” — a network of more than 700 vessels used to bypass international sanctions on oil exports — transports around three-quarters of the country’s sanctioned oil shipments.
The UK has already imposed sanctions on more than 500 ships linked to this trade, because under British sanctions, these vessels are prohibited from entering UK ports and are denied access to financial, insurance and brokerage services provided by British companies.
Tracking data indicates that the Smyrtos, currently anchored near Weymouth, sails under the Cameroonian flag. The tanker departed Russia’s Ust-Luga oil terminal near St. Petersburg on 5 June before entering the Channel over the weekend.
The vessel was sanctioned in July 2025 and has since undergone several changes, including a new name (previously Myrtos) and multiple flag registrations.
The MoD stated that the boarding took place in international waters, more than 12 nautical miles from the British coastline, and was conducted in accordance with both UK and international law.
Officials said the mission followed weeks of military and political preparation. Addressing questions about footage released after the operation, the ministry denied that any scenes had been staged, explaining that cameras were allowed aboard only after troops had secured the vessel.
Support for the operation came from RAF surveillance aircraft, naval forces including HMS Sutherland and HMS Ledbury, and the Maritime Air Group.
Former Armed Forces Minister Al Carns said the mission involved personnel flying at low altitude over the sea before rapidly deploying onto the ship, securing it and escorting it toward British waters. He suggested similar operations could follow if future opportunities arise.
Attorney General Richard Hermer said the government was committed to using international law to target Russia’s shadow fleet, which London views as a key source of funding for the Kremlin’s war effort in Ukraine.
Ukrainian President Volodymyr Zelensky welcomed the action, thanking Britain and urging European countries to adopt tougher measures, including the seizure of oil cargoes carried by sanctioned vessels.
Opposition leader Kemi Badenoch also praised the military personnel involved and reaffirmed her support for continued backing of Ukraine.
The UK government said the operation was closely coordinated with France. Earlier this month, French President Emmanuel Macron revealed that French forces, assisted by Britain, had intercepted another sanctioned tanker suspected of being connected to Russia’s shadow fleet.
Moscow did not immediately comment on the incident, although Russian officials have previously condemned similar actions as unlawful and comparable to acts of piracy.
Prime Minister Keir Starmer described the operation as another setback for Russia, warning that those helping to finance President Vladimir Putin’s war in Ukraine would not be allowed to operate unnoticed.
