Russia’s “shadow fleet” of oil tankers attempting to evade Western sanctions could wreak environmental havoc in Britain’s waters, it has been warned. Moscow is using dangerously old vessels that have been in service for around 20 years to covertly sell fossil fuels to fund the war in Ukraine, the i newspaper reports. More than 90 tankers dating back two decades are said to have sailed past the British coast in the last 12 months, flouting UK maritime rules and risking a “catastrophic” oil spill.

Saleem Khan, chief data officer at maritime intelligence company Pole Star Global, warned that after 20 years, vessels can be impacted by metal fatigue, corroded hulling and structural deterioration. He said: “The Russian shadow fleet is a ticking environmental time bomb. The question isn’t if there will be a catastrophic spill, it’s when.”

Major global oil companies generally err on the side of caution by not operating tankers older than 15 years, and vessels with over 25 years of use are banned from accessing British ports on safety grounds.

While almost all the tankers in Russia‘s shadow fleet are now under sanctions from the UK and its allies, false flag vessels linked to covert operations off the British coast have been identified as up to 27 years old, with structural failures potentially unleashing tens of thousands tonnes of oil.

Pole Star Global estimates that up to £6.8 billion of Russian oil has been shipped through UK coastal and international waters over the last year, with Moscow making around £174 billion from selling fossil fuels around the world in 2025.

While the US and other European countries have taken a more direct approach to tackling illicit trade routes, including tanker seizures in the Indian Ocean and the Mediterranean, the UK has focused primarily on conducting insurance checks.

British troops did assist in the US seizure of the Marinera in January, however, and Defence Secretary John Healey pledged this week to unpick legal obstacles to further action.

He said: “As we enter the fifth year of Putin’s illegal war in Ukraine, we’re stepping up the pressure on Putin by choking off the funds that fuel his invasion and targeting shadow fleet vessels.

“I’m proud of the UK’s leading role in [the multinational Joint Expeditionary Force], as we step up together to tackle the threats we face in this new era for defence.”