British defence planners are preparing options that would allow elite UK forces to board and seize Russian oil tankers operating as part of Moscow's so-called shadow fleet, a move that would mark a significant escalation in the enforcement of sanctions against the Kremlin and carry implications for global shipping and energy markets.
According to multiple defence and government sources cited by British media, the plans would involve deploying the Special Boat Service to conduct maritime interdictions against tankers suspected of transporting sanctioned Russian oil under false flags. The proposals are being developed as part of a broader effort to intensify economic pressure on Vladimir Putin's government.
Officials familiar with the discussions say the legal basis for such actions would rest on the Sanctions and Money Laundering Act 2018, which grants the UK authority to enforce sanctions at sea. Reports from LBC indicate that hundreds of vessels could ultimately fall within the scope of coordinated operations involving the Royal Navy, the Royal Air Force, and NATO partners.
The planning follows Britain's involvement in the recent seizure of the oil tanker Marinera, a Russian-linked vessel captured in the North Atlantic after a two-week pursuit led by U.S. forces with logistical support from the UK. The tanker has been associated with sanctions-evasion networks linked to both Russia and Iran.
UK Defence Secretary John Healey described that operation as a "seamlessly executed operation," language that defence analysts say reflects a growing willingness in London to move beyond financial penalties and into direct interdiction. Analysts cited by iNews have characterised the approach as part of a widening "grey war" between Russia and Western governments.
The shadow fleet-sometimes referred to as the "dark fleet"-consists of hundreds of ageing tankers that often sail without proper insurance, falsify registration details or operate under flags of convenience. Western officials argue that the network allows Russia to continue exporting millions of tonnes of oil, blunting the impact of sanctions imposed after Moscow's invasion of Ukraine.
Security specialists warn, however, that direct seizures could invite retaliation. A Scottish Labour MP told Yahoo News that Britain must be prepared for reprisals, suggesting Moscow could view the UK as a more politically vulnerable target than the United States. The Kremlin has already condemned the Marinera seizure as an "act of piracy."
Maritime analysts also caution that stepped-up enforcement could disrupt commercial shipping lanes and introduce volatility into global energy markets. Even so, defence officials argue the strategy is necessary to undermine Russian war financing. "If you want to dial up the economic pressure on Russia, this is how you do it," one defence source told The Times, as cited by Express.
