Sir Keir Starmer has confirmed that British armed forces carried out a boarding operation on a Russian “shadow fleet” oil tanker in the English Channel in the early hours of Sunday.
Royal Marine Commandos, working alongside specially trained officers from the National Crime Agency and with support from the RAF, intercepted the vessel in an operation that lasted around six hours. They then boarded the tanker for the first time during the mission.
The Ministry of Defence said in a statement that the vessel, Smyrtos, will remain detained and placed under surveillance off the south coast of England while investigations continue.
Sir Keir Starmer said: “This successful operation delivers yet another blow to Russia and reminds those fuelling Putin’s war in Ukraine that we will not let them hide.”
Data from MarineTraffic shows that the Smyrtos is sailing under the flag of Cameroon and is presently anchored off the coast of Weymouth in the English Channel.
BBC Verify reports that the vessel departed on 5 June from Russia’s Ust-Luga port, an oil terminal close to St. Petersburg, before heading westward and entering the English Channel on Saturday.
The vessel was placed under sanctions in July 2025 and has reportedly undergone multiple changes since then, including a name change from Myrtos to Smyrtos, as well as two separate alterations to the flag under which it operates.
Russia is believed to be using a “shadow fleet” of tankers in an effort to bypass international sanctions targeting its oil exports.
According to the Ministry of Defence, the so-called shadow fleet is made up of more than 700 vessels and is responsible for transporting around 75% of Russia’s sanctioned oil exports, serving as a key support mechanism for the Kremlin.
In March, the Prime Minister announced that British armed forces now have the authority to board sanctioned vessels travelling through UK waters.
The Ministry of Defence said the UK has imposed sanctions on more than 500 vessels.
These measures prevent the ships from accessing UK ports and also bar British companies and individuals from offering financial services, insurance, or brokerage support to vessels involved in transporting Russian oil.
The operation comes shortly after a week marked by resignations connected to the government’s Defence Investment Plan (DIP), which is now scheduled for publication before next month’s NATO summit following repeated delays.
Before the plan is released, John Healey stepped down as defence secretary, saying on Thursday that the level of military spending proposed by Sir Keir Starmer “falls well short” of what is required to safeguard the UK.
Al Carns also stepped down as armed forces minister, informing the prime minister that the Defence Investment Plan (DIP) was “neither transformative enough nor sufficiently funded.”
The Sunday operation was backed by aerial support from the Maritime Air Group, an RAF P-8 surveillance aircraft, alongside naval vessels HMS Sutherland and HMS Ledbury.
Speaking to the BBC, Carns said the mission would have required armed forces personnel to “fly at low level over the sea, rise up in front of the vessel, fast rope onto the ship, secure it, and then escort it into UK territorial waters.”
In an interview on Sunday with Laura Kuenssberg, he said that following the UK’s first boarding of a Russian shadow fleet vessel, “we’re probably going to see more, should the opportunities present themselves.”
Following the interception, Attorney General Richard Hermer stated that the government had been clear about its intention to act against Russia’s shadow fleet using the full scope of international law.
He added that the UK is focusing on Russia’s oil income as part of efforts to cut off funding for what it describes as the country’s war effort in Ukraine.
The Ministry of Defence said the Sunday morning operation was carried out in close coordination with France, highlighting it as part of ongoing UK support for allied partners.
On 1 June, French President Emmanuel Macron said that French forces, with support from the UK, had intercepted a sanctioned oil tanker believed to be linked to Russia’s shadow fleet on Sunday.
