Britain is embarking on a bold new venture to defend its critical undersea infrastructure, launching an ambitious suite of surveillance and counter-submarine capabilities under the banner of Atlantic Bastion. Announced on December 8, 2025, the programme marks a significant escalation in the United Kingdom’s efforts to counter what officials describe as a rapidly evolving threat from Russian underwater activity in the North Atlantic and beyond.
Defence Secretary John Healey unveiled the early stages of Atlantic Bastion during a visit to Portsmouth, casting the project as the centerpiece of the Strategic Defence Review’s drive to modernize maritime security. According to BBC and UK Defence Journal, this initiative links together autonomous surface and subsurface vessels, AI-enabled detection networks, and existing naval and air platforms—creating what the government calls a “highly advanced hybrid fighting force.”
“People should be in no doubt of the new threats facing the UK and our allies under the sea, where adversaries are targeting infrastructure that is so critical to our way of life,” Healey warned. He emphasized, “This new era of threat demands a new era for defence, and we must rapidly innovate at a wartime pace to maintain the battlefield edge as we deliver on the Strategic Defence Review.”
The urgency behind Atlantic Bastion is clear. Over the past two years, the Ministry of Defence has documented a 30% increase in Russian vessels threatening UK waters. The Russian intelligence ship Yantar, for example, has operated near British shores, reportedly shining lasers at RAF pilots tracking its progress—a move Healey described as “deeply dangerous.” UK Defence Intelligence has assessed that Russia is aggressively modernizing its submarine fleet, with the apparent goal of holding at risk the undersea cables and pipelines that power Europe, carry global financial data, and underpin NATO’s communications.
“We know the threat that Russia poses,” Healey told BBC. “We track what their ships do. We track what their submarines are doing. We know that they are mapping our undersea cables and our networks and our pipelines, and we know that they are developing new capabilities all the time to put those at risk.”
Atlantic Bastion aims to counter this challenge with a multi-layered, integrated network. According to Reuters and UK Defence Journal, the system will combine crewed warships, submarines, unmanned platforms, and distributed acoustic sensors powered by advanced AI analytics. The Royal Navy’s new SG-1 Fathom glider, made by the German firm Helsing and currently being trialled, exemplifies this approach. As described by programme manager Katie Raine, the Fathom glider “patrols through the depths of the ocean monitoring and listening for adversaries that might be in the area,” using software trained on decades of acoustic data to detect threats more rapidly than ever before.
If successful, Fathom and similar technologies will become core elements of Atlantic Bastion’s surveillance web—capable of patrolling for months on end, working autonomously alongside dozens of other drones, and feeding real-time data into a fused sensor-to-shooter system. The vision, according to the Ministry of Defence, is to anticipate and neutralize threats before they can disrupt the UK’s vital undersea lifelines.
Industry engagement has been robust. The Ministry of Defence has already allocated £14 million in seed funding, with private investment matching public money at a ratio of four to one. Twenty-six companies have submitted sensor concepts, and twenty firms are demonstrating early systems, with selected technologies expected to enter water trials in 2026. Dr. Rich Drake of Anduril UK told UK Defence Journal, “The government has called upon industry to create the modern warfighter. We have designed Seabed Sentry in the UK in partnership with other British companies to deliver for our Armed Forces and protect allied waters from increasingly hostile actors.” He added that Anduril is investing in “British talent, British technology and Britain’s tomorrow.”
BAE Systems and Helsing have also touted the transformative potential of autonomy and AI in underwater warfare. Scott Jamieson of BAE Systems highlighted the firm’s Herne extra-large autonomous submarine and its control system, Nautomate, as technologies that “deliver enhanced tactical flexibility, enable data driven mission decisions and scale operations in ways that were previously unimaginable.” Amelia Gould of Helsing stated, “Through self-funded development and UK-based trials of SG 1 Fathom and Lura, we have demonstrated the power of advanced AI and autonomy to change the game in the underwater battle space.” Helsing, she said, is ready to “create a sea drone wall to protect NATO.”
The strategic importance of these innovations has not gone unnoticed by Britain’s military leadership. The First Sea Lord, General Sir Gwyn Jenkins, is expected to expand on Atlantic Bastion’s role at the International Sea Power Conference, arguing that “the maritime domain is increasingly vulnerable and that maritime security is a strategic imperative for the UK. It is time to act.” In his prepared remarks, Jenkins calls Atlantic Bastion “our bold new approach to secure the underwater battlespace against a modernising Russia” and a “revolutionary underwater network—more autonomous, more resilient, more lethal and British built.”
Jenkins is candid about the scale of the challenge. “Despite the cost of the war in Ukraine to [Russia], they continue to put hundreds of billions of dollars’ worth of investment into their submarine fleet,” he told BBC. “We’re still ahead in the Atlantic, but it’s not by as much of an advantage as I would like. We’re being pressed, and we’re definitely in the competition to stay ahead of where the Russians are.”
Atlantic Bastion’s unveiling comes as the UK seeks to deepen cooperation with allies. In early December, Defence Secretary Healey and his Norwegian counterpart signed the Lunna House Agreement, a defence pact to jointly hunt Russian submarines and protect underwater infrastructure. The move underscores the transatlantic nature of the threat and the need for a coordinated response.
Yet not everyone is convinced the Royal Navy is fully prepared. Professor Peter Roberts of the Royal United Services Institute told BBC that while the new strategy “looks fine on paper,” he believes the Navy lacks sufficient resources and is “trying to find a way to look credible” in the face of a steadily increasing threat. “The Royal Navy does not have the ships to do this job coherently or credibly and is looking to address it with drones as they are cheaper and can provide coverage of the geographical areas for which the Royal Navy is responsible in lieu of new ships,” Roberts argued. “Russia so far is going unchallenged in much of UK water space and this strategy is playing catch up long after the fact.”
Russian officials, for their part, have dismissed Britain’s moves as provocative. Russian Foreign Ministry spokesperson Maria Zakharova accused the UK of “monitoring Russian naval activity” and warned that the new defence pact risked “provoking unnecessary conflicts” in international waters.
For now, British officials remain resolute. They argue that Atlantic Bastion is not only a technological leap but an urgent necessity—one that will integrate naval, air, and digital assets into a single system capable of detecting and responding to threats at speed across the North Atlantic. As the first devices prepare to enter water trials next year, the eyes of the defence world will be watching to see whether Atlantic Bastion can live up to its promise of keeping the UK secure at home and strong abroad.