The United Kingdom is accelerating work on a new undersea defence network, codenamed ‘Atlantic Bastion’, in response to increased Russian activity around critical subsea infrastructure, including the recent presence of the Russian intelligence-gathering vessel Yantar near British waters.

The programme was outlined in more detail on Monday by senior Royal Navy leaders, including the First Sea Lord, General Sir Gwyn Jenkins, who is giving an update at the International Sea Power Conference in London. Atlantic Bastion was first announced as part of the Strategic Defence Review and is being developed as a dedicated system for monitoring and protecting seabed assets such as cables and pipelines.

According to the Ministry of Defence, the project is a direct response to a resurgence of Russian submarine and underwater activity in the North Atlantic, highlighted by the Yantar’s movements close to the UK’s exclusive economic zone last month. The vessel, officially described by Moscow as a research ship, is assessed in London as belonging to a specialist branch of Russia’s armed forces and capable of mapping or disrupting undersea infrastructure.

In a recent incident north of Scotland, British officials say Yantar directed lasers at Royal Air Force surveillance pilots who were monitoring its route. Defence Secretary John Healey described that episode as “deeply dangerous” and warned that the UK was prepared to respond if the ship altered course towards more sensitive areas. Russian authorities have rejected the allegations and dismissed British concerns about the vessel’s activities.

Atlantic Bastion is intended to knit together crewed and uncrewed systems into a single networked force. The MoD says the concept will link surface ships, submarines, aircraft and unmanned vessels through artificial-intelligence-driven acoustic detection, feeding data into a digital targeting web designed to identify and track hostile platforms more quickly than at present.

The programme has attracted £14 million in combined funding from the MoD and industry during 2025. A total of 26 companies from the UK and other European states have submitted proposals, ranging from sensors and underwater drones to data-processing tools. Defence planners hope that initial elements of the system can begin entering service as early as next year, following further trials and evaluation.

Mr Healey visited the naval base at Portsmouth last week to view some of the prototype systems being considered for Atlantic Bastion. Demonstrators included the ‘Rattler’ unmanned surface vessel, the SG-1 Fathom autonomous underwater glider, an experimental uncrewed submarine known as Excalibur, and a model of an autonomous anti-submarine helicopter called Proteus. These platforms are being tested for roles such as long-duration patrol, cable-route monitoring and rapid response to suspicious activity.

“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,” Mr Healey said during the visit, linking Atlantic Bastion to a wider push to modernise the Royal Navy’s anti-submarine and undersea surveillance capabilities.

The First Sea Lord is expected to present Atlantic Bastion as a central element in securing what he has called the “underwater battlespace” against a modernising Russian navy. In his prepared remarks, Sir Gwyn argues that the maritime domain has become more vulnerable and that undersea security is now a strategic imperative for the UK, particularly in the North Atlantic routes connecting Britain with continental Europe and North America.

The focus on seabed infrastructure reflects its growing strategic importance. Subsea cables carry the vast majority of global internet and financial data traffic, while offshore pipelines and interconnectors supply electricity, oil and gas between the UK and its neighbours. British officials have repeatedly warned that these assets present potential targets for hostile states in a crisis, and that traditional maritime surveillance alone is no longer sufficient to protect them.

The undersea initiative is also closely linked to a new bilateral defence agreement with Norway, signed in London on 4 December. Under the so-called Lunna House Agreement, the Royal Navy and the Royal Norwegian Navy will operate an interchangeable fleet of at least 13 British-built Type 26 anti-submarine frigates, supported by autonomous systems, to hunt Russian submarines and safeguard cables and pipelines in the North Atlantic, including the Greenland–Iceland–UK gap.

London and Oslo say Russian naval movements threatening UK waters have risen by around 30% over the past two years, and both governments now frame protection of critical underwater infrastructure as a core mission for their fleets. The UK–Norway agreement provides for joint patrols, shared maintenance facilities and common munitions, as well as collaboration on uncrewed mine-hunting and undersea warfare vessels, which are likely to be compatible with Atlantic Bastion’s sensor and communications architecture.

Taken together, Atlantic Bastion and the Lunna House pact illustrate a shift in UK maritime defence policy towards networked, technology-heavy solutions and deeper regional cooperation. While the sums invested so far are modest by defence standards, officials expect further contracts once the initial prototypes have been assessed, and they have signalled that allied navies could tap into the architecture as it matures.

For now, the core elements of Atlantic Bastion remain in the development and testing phase. The MoD is evaluating industry proposals and trial data from this year’s demonstrations at Portsmouth and other sites. If the system enters service on the timetable outlined by defence chiefs, it is expected to form part of a broader NATO effort to monitor Russian activity in the High North and across the North Atlantic, with the aim of making any interference with European undersea infrastructure more difficult to carry out and easier to attribute.

Main Image: By Ian Dick from Glasgow, UK – HMS Glasgow, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=127295484