British forces have boarded and seized a sanctioned Russian shadow fleet oil tanker in the English Channel, the first time the United Kingdom has led such an operation in its own waters. The vessel, named Smyrtos and sailing under a Cameroon flag, was taken in the early hours by Royal Marine commandos and officers from the National Crime Agency. The operation, which reportedly lasted around six hours, was supported by helicopters, an aircraft and Royal Navy ships including the frigate HMS Sutherland. The tanker was then moved to an anchorage off the south coast of England to be held and monitored as investigations continue. Prime Minister Keir Starmer framed the seizure in stark terms, saying it delivered another blow to Russia and reminded those fuelling the war in Ukraine that they cannot hide. The action follows his decision earlier in the year to authorise British forces to intercept shadow fleet vessels passing through UK waters. The so called shadow fleet is a sprawling collection of ageing tankers, often with opaque ownership, that Russia uses to keep exporting oil despite Western sanctions. By some estimates the fleet now numbers more than 700 vessels and carries a large share of Russia's sanctioned oil, making it a critical lifeline for the Kremlin's war economy. Britain's stated aim is to close its waters to these ships and force them onto longer and costlier routes, raising the price of moving Russian crude. The move also lands at a politically useful moment, giving London a concrete result to point to as allies coordinate pressure on Moscow. Other European navies, including those of France, Belgium and Finland, have carried out similar interceptions. The Channel seizure signals that the net around the shadow fleet is tightening. Source: [Al Jazeera](https://www.aljazeera.com/news/2026/6/16/uk-seizes-russian-shadow-fleet-tanker-what-that-means)