British naval forces have once again found themselves at the center of rising tensions in European waters, after tracking a Russian Kilo-class submarine and its escort for three days through the English Channel. The operation, which began on December 11, 2025, involved the stealthy submarine Krasnodar and the tug Altay, both of which entered the Channel from the North Sea and passed through the Strait of Dover. According to statements from the Royal Navy, the mission underscores what London describes as a sharp uptick in Russian naval activity near the United Kingdom—a trend that has British officials sounding the alarm and investing heavily in maritime defense.
The Royal Navy’s response was measured but robust. A British naval supply ship, the RFA Tidesurge, equipped with an on-board Merlin Mk2 helicopter from 814 Naval Air Squadron, was deployed to shadow the Russian vessels. The Merlin, a formidable anti-submarine warfare platform, was ready to pivot into full combat mode had the Krasnodar submerged. But as fate would have it, the submarine remained on the surface throughout its passage, despite rough seas and unfavorable weather. "Expert aircrew were prepared to pivot to anti-submarine operations if Krasnodar had dived below the surface," a Royal Navy statement noted, highlighting the ever-present readiness of British forces.
As the Russian group approached the waters off Ushant (Ouessant) Island in northwestern France, the Royal Navy handed over monitoring duties to a NATO ally, continuing the tradition of allied cooperation in these strategically vital waters. While the identity of the NATO partner was not disclosed, this seamless handover reflects the broader unity within the alliance when it comes to countering perceived Russian incursions.
This is hardly the first time such an operation has taken place. Back in July 2025, British forces conducted a similar shadowing mission after detecting another Russian Kilo-class submarine, the Novorossiysk, near British territorial waters. These repeated encounters have become emblematic of what British officials now call the "new normal" in the Channel and North Atlantic approaches.
Why all the fuss over a single submarine transit? For starters, the Kilo-class—especially the Project 636.3 Improved variant like the Krasnodar—is no ordinary vessel. According to open-source data cited by Army Recognition, the submarine boasts a submerged displacement of roughly 3,100 tons, an operational depth of about 240 meters, and patrol endurance measured in weeks. Its arsenal includes six 533-mm torpedo tubes capable of launching heavyweight torpedoes, laying mines, and firing Kalibr cruise missiles. In other words, it’s a formidable adversary, and its presence so close to British shores is anything but routine.
"There is nothing like a Russian submarine to focus the mind for any mariner," Royal Navy Captain James Allen remarked, summing up the seriousness with which these operations are undertaken.
The tactical posture of the Royal Navy during these missions is intentionally visible, designed to send a clear deterrent message to Moscow. The RFA Tidesurge, while primarily a supply and refueling vessel for the Queen Elizabeth–class aircraft carriers, can serve as a floating aviation base for helicopters like the Merlin, Wildcat, and even the massive Chinook. This flexibility allows the Royal Navy to adapt quickly, turning logistical platforms into frontline assets when needed.
But the story doesn’t end with a single submarine. British defense officials say that Russian naval activity near the UK has increased by about 30%—or "about a third"—over the past two years. This includes not just submarines but also reconnaissance ships like the Yantar, which Western officials suspect of mapping undersea cables. In late November, a Russian intelligence vessel reportedly directed lasers at Royal Air Force pilots tracking its activity near UK waters, a move that British Defense Secretary John Healey described as part of Moscow’s broader campaign of "underwater threats." According to BBC News, Healey announced a multi-million pound program to enhance the Royal Navy’s capabilities in response.
Meanwhile, the UK is not facing these challenges alone. In early December 2025, London and Oslo inked a cooperation agreement to jointly operate a fleet of frigates tasked with hunting down Russian submarines in the North Atlantic. This partnership is part of the wider Atlantic Bastion initiative, which leverages autonomous systems, artificial intelligence, surface ships, and aircraft to protect critical infrastructure—including the undersea cables that carry 99% of Britain’s international data traffic and the continuous at-sea nuclear deterrent centered at HMNB Clyde and RNAD Coulport.
The legal framework governing these transits is complex. Under the United Nations Convention on the Law of the Sea, Russian vessels are permitted to pass through these waters, provided submarines conducting "innocent passage" remain on the surface and display their flag. Still, the line between legal navigation and intelligence-gathering is thin, and British officials have grown increasingly concerned about the risk to vital undersea infrastructure. A UK parliamentary inquiry recently emphasized that the country’s roughly 60 undersea cables are a core national security issue.
It’s not just official navies getting involved, either. Earlier in December, a group of volunteer scuba divers off the coast of Wales recovered what experts believe to be a Russian sonar buoy, likely designed to track submarines. This unexpected find further stoked concerns that Russian activity in the region is not merely routine transit but part of a broader campaign of surveillance and seabed reconnaissance.
The geopolitical backdrop to these maritime maneuvers is as tense as ever. NATO Secretary-General Mark Rutte, speaking in Berlin, issued a stark warning: "We are Russia’s next target." He urged Europe to prepare for confrontation on a scale reminiscent of the mid-20th century. Britain’s armed forces minister, Al Carns, echoed this sentiment, stating, "The shadow of war is knocking on Europe’s door once more. That’s the reality. We’ve got to be prepared to deter it."
As Russian vessels continue to test the boundaries of international norms and NATO’s resolve, the Royal Navy’s recent operation serves as a vivid reminder of the stakes at play. These are not isolated incidents, but rather signs of a shifting security environment—one in which vigilance, coordination, and technological innovation are more important than ever.
The three-day tracking of the Krasnodar may have ended with a routine handover to NATO partners, but for many in Britain and across Europe, the message is clear: the Channel and the North Atlantic are once again frontlines in a contest for maritime supremacy and strategic stability.
