Prime Minister Keir Starmer has authorised the military and law enforcement agencies to detain vessels belonging to Russia’s “shadow fleet” in British territorial waters.
The announcement was made by Downing Street on 25 March 2026. The decision enables the UK Armed Forces and law enforcement officers to intercept, inspect and, where necessary, detain vessels on UK sanctions lists that are suspected of transporting Russian oil in circumvention of Western sanctions.
According to Starmer, the measure is aimed at “strangling Putin’s war machine by cutting off the dirty revenues that fund his barbaric campaign” in Ukraine. The Prime Minister noted that Putin, in his view, is “rubbing his hands” over rising oil prices amid conflicts in the Middle East.
British military personnel — including the Royal Marines — and police will have the authority to stop sanctioned vessels in UK territorial waters, including in the English Channel.
Ministers had previously identified a legal basis for such action under the Sanctions and Anti-Money Laundering Act 2018.
The first such operation may take place in the near future. Vessels that fail to comply with orders to stop, are found to be armed, or are using tracking systems to evade detection will be subject to forced boarding and inspection.
The UK has already imposed sanctions on hundreds of shadow fleet vessels — a network of often ageing tankers with opaque ownership structures, false flags and disabled transponders, which enable Russia to export oil despite the G7 price cap. London is coordinating its efforts with northern European allies through the Joint Expeditionary Force (JEF).