The UK is threatening to seize Russia-linked shadow fleet tankers. British defence sources confirmed that military plans have been discussed with NATO allies. This move could open a new front against Moscow as Russian oil income falls. In January, 23 shadow fleet ships using false flags appeared in the Channel or Baltic Sea. They mainly export Russian oil to China, India, and Turkey. A joint statement from the UK, Germany, France, and NATO countries said all ships in these waters must follow international law. "The Royal Navy could challenge any number of ships under maritime law because they are in fact stateless," said Richard Meade, editor-in-chief of Lloyd’s List. However, the UK has avoided action to avoid escalating tensions. The Royal Marines reportedly expressed eagerness to seize one of these vessels. A month ago, the US seized the Russian tanker Marinera in the north Atlantic, with British help. This tanker had changed flags to avoid capture but was caught. Richard Meade said a UK or European-led seizure could cause a stronger Russian reaction. France seized the oil tanker Grinch off Spain in January but released it due to French law. UK Defence Secretary John Healey said Britain will hold talks with Baltic and Nordic countries about military options. Captured oil could be sold to support Ukraine. Russia produces around 10 million barrels of oil daily, with 5-6 million barrels shipped by sea mostly to China and India. After western sanctions, Russia created a "shadow fleet" of aging tankers flying false or weak flags to evade controls. Gonzalo Saiz Erausquin of the Royal United Services Institute called them poorly maintained and opaque in ownership. False flag ships are considered stateless and can be legally seized, though rules vary in Europe. Since November, seven shadow tankers were hit by drones, with Ukraine claiming four attacks. Despite this, Russian oil exports remain above 5 million barrels a day. Russia is re-registering some shadow fleet vessels under its own flag to avoid seizures. More than 200 shadow fleet ships linked to Russia are still active. Russia’s own flagged fleet is growing, currently handling 51% of exports. The UK’s tough talk comes as Russia’s economy weakens, with oil revenues down 24% in 2025. EU is considering banning maritime services to Russian ships, which experts say could strongly impact Moscow, especially if combined with military action.