Russian submarine and spy ship Yantar operated together in British waters in November 2023, mapping a gas pipeline linking Britain and Ireland amid increased Russian incursions.

A Russian submarine was deployed alongside the Russian spy ship Yantar to map critical undersea infrastructure, specifically a gas pipeline linking Britain and Ireland, in British waters. The Ministry of Defence declassified a photo showing the submarine shadowing the Yantar. An anti-submarine Merlin Mk2 helicopter and a British submarine were also observed tracking the Yantar in the Irish Sea in November 2023. This operation is considered one of several instances where Russian submarines have accompanied the Yantar near the British Isles. The UK Royal Navy First Sea Lord, General Sir Gwyn Jenkins, reported a 30% increase in Russian incursions in UK waters over the last two years, noting concerns about undersea activities. The UK government has responded with increased defense spending, new sanctions against Russian individuals and entities, and accelerated anti-submarine technological development through the Atlantic Bastion programme to protect critical undersea infrastructure.