Britain is scaling up action against President Vladimir Putin’s so-called shadow fleet after helping the United States seize an oil tanker suspected of evading international sanctions following a weeks-long pursuit across the Atlantic.
The vessel, Marinera, previously known as Bella 1, was intercepted by US forces in the North Atlantic on Wednesday during an operation supported by UK surveillance aircraft and a Royal Navy support ship. Sources said British and American officials had been planning the mission for at least a week after the tanker slipped through a Venezuelan maritime blockade.
The seizure has raised tensions with Moscow, which accused the West of breaching international maritime law and warned the incident could become a new flashpoint in relations with Nato countries.
According to US Southern Command, another Venezuela-linked tanker, Sophia, was seized in the Caribbean on the same day. Both vessels are suspected of being used to bypass sanctions on oil exports.
The Ministry of Defence said the UK’s role in the operation was in full compliance with international law, stressing that British involvement was part of a wider effort to disrupt Russia’s shadow fleet rather than targeting Venezuela.
Defence Secretary John Healey told MPs that Marinera had transported more than seven million barrels of Iranian crude oil over the past four years, with proceeds allegedly used to fund terrorism, threats and instability around the world.
He said the tanker also had close links to Moscow and described it as significant that the vessel began sailing under a Russian flag after the United States first attempted to intercept it. “The UK will not stand by as malign activity increases on the high seas,” Healey said. “We are stepping up our response against shadow vessels and we will continue to do so.”
Healey said the operation highlighted the increasingly unpredictable global security environment and described the shadow fleet as vital to Russia’s ongoing invasion of Ukraine. A Ministry of Defence source said further operations against Russian-linked vessels had not been ruled out.
The Pentagon is understood to have requested British assistance shortly before the new year. Healey briefed the prime minister and legal advice was sought on the participation of UK forces. Although Marinera was re-registered under a Russian flag on Christmas Eve, government lawyers concluded the vessel was effectively stateless and that the change of registration was not valid. UK and US officials have continued to refer to the ship as Bella 1.
Downing Street confirmed that Prime Minister Sir Keir Starmer discussed the seizure with President Trump, describing it as part of shared efforts to clamp down on sanctions evasion.
The tanker has operated under six names since 2020 and sailed under the flags of five different countries. It is subject to US sanctions over alleged links to Iranian oil exports and was assessed by the Ministry of Defence to have used false flags while engaging in illegal activity connected to Hezbollah.
US forces pursued the vessel for several weeks after it reportedly escaped what President Trump described as a total naval blockade of Venezuela imposed in December. It was seized as it sailed between Iceland and Scotland, apparently bound for the Russian Arctic port of Murmansk.
British support included the deployment of an RAF Rivet Joint surveillance aircraft, a P-8 Poseidon maritime patrol aircraft and the Royal Fleet Auxiliary ship RFA Tideforce. The UK also allowed US aircraft and personnel to operate from British bases. US special operations forces were later filmed abseiling onto the tanker from helicopters in difficult Atlantic sea conditions.
Healey praised the courage and professionalism of US forces and said the operation demonstrated the strength of the UK-US defence partnership.
The tanker, which was empty at the time of seizure, is expected to be taken to the United States. White House press secretary Karoline Leavitt said the crew could face prosecution, adding that Washington would fully enforce sanctions policy.
Russia demanded the crew’s release, with its transport ministry insisting the ship was lawfully registered under the Russian flag. Kremlin adviser Andrei Fedorov warned the seizure could trigger a serious crisis in relations between Moscow and Washington, although he said Russian submarines escorting the vessel would not use force.
