Royal Navy did not detain “shadow fleet” ships in English Channel due to concerns about violating international law, The Telegraph reports

British authorities chose not to stop the vessels due to concerns about breaching international law, which imposes strict legal requirements on states seeking to board foreign ships. In the event of a boarding, officials would later be required to present a legally sound justification for each interception and prove that the vessel had indeed violated UK sanctions.

These legal constraints undermined Starmer’s pledge, made two weeks earlier, to crack down on the “shadow fleet.” At the time, he authorized British military and law enforcement personnel to detain sanctioned vessels located in the country’s territorial waters. The government had hoped that the announcement would force operators to reroute sanctioned vessels along longer and less profitable paths.

Tankers have indeed increasingly opted for routes that avoid UK waters, with some entering the Atlantic Ocean by sailing around Ireland. In early April, an unprecedented number of these vessels was observed off Ireland’s west coast.

Since January, more than 300 vessels linked to Russia’s “shadow fleet” have passed through UK territorial waters, according to The Telegraph. Experts cited by the newspaper also noted that seizing such a large number of tankers would require significant resources, and British ports have a limited number of berths capable of accommodating vessels of that size.