UK intercepts India-bound shadow fleet oil tanker 'Smyrtos': Why this is a major first

In a crucial operation on Sunday, the UK's armed forces boarded the Russian shadow fleet oil tanker Smyrtos (IMO: 9389100) while it was trying to cross the English Channel.

The unflagged Aframax tanker, which had left from Russia's Ust-Luga Port, was en route to the Sikka Port in India with 101,400 tonnes of Ural crude, as per maritime tracker Lloyd's List.

However, it was intercepted mid-transit by a group of Royal Marine Commandos and specially trained law enforcement officers from the National Crime Agency (NCA).

The six-hour-long operation was supported with aircraft from the Maritime Air Group (Chinooks, Merlin Mk4 and Wildcat) and a P-8 aircraft from the RAF, as well as two warships—the HMS Sutherland and the HMS Ledbury.

Despite taking place in English waters, this is touted as a major first for the UK, which has never intercepted such vessels in the history of the four-year-long Russia-Ukraine war.

What is the shadow fleet?

Shadow fleet ships are those that transport sanctioned products like crude oil in and out of countries like Russia, Iran, and China.

These vessels often use a number of techniques, like turning off their AIS transponders, to evade detection.

Behind the UK-led interception of the Smyrtos

Notably, the UK has already sanctioned almost 600 vessels linked to Moscow to date, according to its Ministry of Defence (MoD).

However, it never boarded any of them over fears of violating international law, which often sparked backlash against the Keir Starmer-led government for its failure to live up to its promises of stopping sanctioned ships.

Things came to a head two months ago, when Russia sent one of its Black Sea frigates, the Admiral Grigorovich, to escort two shadow fleet tankers through English waters.

This transit on April 8 was seen as an open challenge to Starmer's warning that the UK would "go after" the shadow fleet in its territorial waters.

A day later, The Telegraph reported that Lord Hermer, the UK's Attorney General (AG), had pointed out that ships could be boarded by special forces and NCA officers, which was not being done due to the complex legal paperwork that would follow.

The point of the paperwork was to legally prove that the "interdiction", as it is formally called, was linked to the vessel evading British sanctions.

However, in the case of the Smyrtos, which has been sanctioned by the UK since October 2025, what finally led to the interception was its flag.

The Lloyd's List report has noted that due to EU pressure, the ship had recently lost its registration with Cameroon, whose flag it had been flying since December 2025.

Though it made plenty of transits in English waters in the past, the loss of its flag was the legal trigger because it meant a loss of protection under international law. 

International laws like the UNCLOS Article 110, as well as UK-based ones such as the Russia (Sanctions) (EU Exit) Regulations 2019—as well as criminal and maritime enforcement powers under the Policing and Crime Act 2017—were suddenly more justifiable, which is said to have aided the decision.

"The Smyrtos will be provisionally moved to an anchorage off the South Coast of England and will be monitored for any environmental or safety concerns," the MoD statement said.