The Royal Navy has tracked a Russian Kilo-class submarine and its support vessel during a surfaced transit through the North Sea and English Channel, in what defence officials regard as a demonstrative show of presence close to NATO critical infrastructure.

On 2 July, HMS Mersey, a Portsmouth-based River-class offshore patrol vessel, was deployed to monitor the Russian submarine Novorossiysk and the accompanying Goryn-class tug Yakov Grebelski. The patrol was conducted in coordination with two helicopters— a Wildcat from 815 Naval Air Squadron and a Merlin Mk2 from 824 Naval Air Squadron—both operating from Royal Naval Air Stations in Yeovilton and Culdrose respectively.

According to the Royal Navy, the Russian vessels remained on the surface for the duration of the transit. The decision to travel surfaced in such a busy and strategically sensitive maritime zone is considered by analysts to serve both navigational and strategic signalling purposes.

The operation formed part of the United Kingdom’s commitment to maintaining situational awareness in national and adjacent international waters, while also contributing to broader NATO surveillance activity.

“Monitoring the transit of naval vessels through our area of responsibility remains a fundamental task,” said HMS Mersey’s Commanding Officer, Lieutenant Commander Dan Wardle. “One that ensures we maintain situational awareness and the ability to respond swiftly when required.”

Lt Cdr Wardle added: “This operation is another clear demonstration of the Royal Navy’s enduring commitment to safeguarding the United Kingdom’s maritime interests. I am proud of my ship’s company, whose professionalism, cohesion, and constant readiness continue to reflect the high standards expected of Royal Navy personnel.”

The Wildcat helicopter provided surface reconnaissance using electro-optical and radar sensors, while the Merlin Mk2—optimised for anti-submarine warfare—deployed sonar and magnetic detection equipment. For 824 NAS, based at RNAS Culdrose, the deployment formed part of operational training. “This opportunity allowed 824 NAS to expose junior aircrew to reactive operations in cooperation with HMS Mersey to protect UK waters,” said Commander Alex Kelley.

This was the sixth such deployment for HMS Mersey in three months, reflecting an uptick in Russian naval activity near British territory. The operation followed another tracking mission only a week earlier, involving HMS Duncan and HMS Trent, which shadowed the Russian frigate Admiral Grigorovich and the corvette Boikiy—both vessels configured for anti-submarine and long-range missions.

The surfaced transit of the Novorossiysk comes amid heightened attention to maritime security in the North Sea and the Channel, regions that host undersea pipelines, communications infrastructure, and major commercial shipping lanes. UK defence officials have repeatedly emphasised the importance of persistent monitoring to prevent disruption and avoid unintended escalation.

Following the exit of the Russian vessels from UK waters, HMS Mersey handed over monitoring duties to allied NATO forces. The Wildcat and Merlin aircraft returned to their respective bases in Somerset and Cornwall.

Defence planners in London have noted the increasing visibility of Russian naval movements near the UK, with multiple submarine and surface ship transits recorded since the start of the year. In a separate incident earlier this year, the Boikiywas seen escorting two sanctioned Russian oil tankers—part of the so-called “shadow fleet”—through the English Channel, marking the first documented case of a Russian warship providing protection to such vessels in the area.

The UK government has committed to expanding maritime defence capabilities, with spending set to rise to 2.6% of GDP by 2027, and further increases projected in the next parliamentary cycle. These measures aim to strengthen NATO’s northern maritime defences and support Britain’s capacity to detect, deter, and respond to naval activity near its coastlines.

The latest operation underscores the Royal Navy’s continuing role in frontline surveillance and demonstrates the practical integration of British and NATO maritime assets in response to evolving security challenges in European waters.

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