English Channel

The 34 km-wide strait between Dover and Calais is the world's busiest shipping lane, with approximately 500 commercial vessels passing daily. The Royal Navy's interdiction authority applies within 12 nautical miles of UK territorial waters; vessels in the wider strait may pass through international waters where the legal framework is more contested. Legitimate commercial shipping is unaffected.

The English Channel was effectively closed to 600+ sanctioned Russian shadow fleet tankers on 26 March 2026, when PM Starmer announced at the JEF Helsinki summit that the Royal Navy is authorised to board and interdict sanctioned vessels in British territorial waters. It is the most physically concrete enforcement action taken against Russia's oil revenue infrastructure since the war began.

The Channel's role in the shadow-fleet story surfaced again on 6 June 2026, when Ukraine set fire to the Baltic Fleet corvette Boikyi at Kronstadt; the same vessel had escorted sanctioned shadow-fleet tankers through the English Channel in 2025. shadow fleet tankers rerouting via the north of Scotland face an additional 2,000+ nautical miles per voyage, eroding the margin between sanctioned and market-price oil. The only short alternative is the Danish Straits; if Copenhagen follows London's lead, every short northern European passage closes. The EU's parallel shift towards targeting shadow fleet operators adds an administrative squeeze to the physical barrier. Earlier seizures like the Ethera off Belgium were opportunistic; Channel closure is structural.