The UK government has defined the legal basis which, according to ministers, allows the country’s armed forces to board and detain ships of the so-called “shadow fleet” used to circumvent international oil sanctions. This was reported by BBC News, citing government sources.
The Sanctions and Anti-Money Laundering Act 2018 could become a key legal instrument. According to the authorities’ interpretation, it allows the use of military force against ships that do not have a valid national flag — a common practice of Russia, Iran, and Venezuela’s “shadow fleets” to evade sanctions.
To date, the UK has already imposed sanctions on more than 540 vessels suspected of belonging to the “shadow fleet.” According to the authorities’ estimates, these measures have already taken about 200 tankers out of service and reduced Russia’s oil export capacity by about 27% compared to October 2024.
The recent detention of the tanker Marinera prompted the acceleration of work on the mechanism. On January 7, 2026, the US military, with the support of the Royal Fleet Auxiliary and the Royal Air Force, seized the vessel in international waters in the Atlantic Ocean. The tanker is accused of transporting oil in violation of US sanctions in the interests of Russia, Iran, and Venezuela.
So far, the British military has not conducted any independent operations to detain ships, but according to sources, the government is actively discussing when and how to use its new powers. Officials emphasize that the fight against the “shadow fleet” remains a priority and that actions will be intensified in coordination with allies.