The United Kingdom has defended a High Court operation that saw a Russian "shadow fleet" tanker, the MT Smyrtos, seized in the English Channel after the Kremlin’s president promised to respond in kind to further seizures.

The chartered vessel, docked off Weymouth, was boarded by Royal Marine Commandos in a first‑of‑its‑kind raid that allegedly disrupted the sanctioned tanker in June. Royal Marines seized the ship and detained its captain, Ajay Pant, who has been charged with breaching Russian sanctions by allowing the delivery of Russian oil.

Putin, while on a Pacific‑fleet drill, criticised the UK and other Western nations for "seizing our vessels" and said Russia would retaliate wherever it deemed necessary. The Ministry of Defence emphasised that the operation was fully compliant with international maritime law and that UK forces operate within that framework.

Russia is believed to run a shadow fleet of more than 700 vessels carrying roughly 75% of sanctioned oil – a lifeline for Vladimir Putin’s war in Ukraine. The EU has over 630 sanctioned vessels, banning them from EU ports and detaining suspected tankers in various theatres, including the Mediterranean, where the Italian navy boarded a tanker on suspicion of false flagging.

Other Western countries have seized or detained Russian‑linked vessels or carried out boardings when sanctions violations were suspected, so the UK’s seizure is part of a wider effort to curb Russia’s illicit oil traffic.

A military personnel on a helicopter above a large vessel, wearing green tactical gear and helmet