British forces played a supporting role in a high-profile U.S. operation to seize a Russian-flagged oil tanker in the North Atlantic that Washington says was part of a sanctions-evasion network linked to Venezuela, Iran and Russia.

On January seventh, U.S. forces moved against the vessel now called Marinera, formerly known as Bella 1, after tracking it for weeks as it traversed international waters from the Caribbean toward northern Europe.

The United Kingdom’s Ministry of Defence confirmed that it provided pre-planned operational backing — including Royal Air Force aerial surveillance, access for U.S. aircraft to British bases and logistical support from the Royal Fleet Auxiliary — while U.S. forces conducted the actual boarding and seizure of the tanker.

The operation formed part of a broader campaign to enforce sanctions on “shadow fleet” vessels that Washington asserts are used to transport crude oil in breach of Western restrictions.

Defence Secretary John Healey described the collaboration as fully compliant with international law and emphasised the strength of the trans-Atlantic security partnership.

He noted that although British personnel did not board the vessel, the surveillance and support provided were instrumental to the mission’s success, which unfolded roughly between Iceland and Scotland.

The U.S. Coast Guard, supported by U.S. Navy aircraft and helicopters, carried out the boarding after a prolonged pursuit that began late last year when Bella 1 attempted to evade U.S. interception by altering its flag and name amid sanctions enforcement efforts.

According to authorities, the tanker had repeatedly changed names and registry to obscure its status and was sanctioned for alleged ties to illicit cargo movements, including oil shipments linked to Iran and Venezuela.

The seizure has drawn condemnation from Russia’s foreign ministry, which labeled the action a violation of international maritime norms and warned of potential escalation, while Kyiv and other Western capitals have framed the operation as a decisive blow against networks that help finance destabilising activity abroad.

Analysts say the incident highlights the increasing use of combined military and legal measures by Western states to counter “shadow fleet” vessels that exploit flag-state ambiguities to skirt sanctions regimes.

Britain’s involvement signals both its continued alignment with U.S. enforcement priorities on sanction evasion and the strategic importance placed on securing critical maritime domains in cooperation with allies, even as legal questions about jurisdiction and the use of force at sea persist in diplomatic arenas.