Russian Spy Ships Near UK Waters: Why Britain’s Undersea Cables Are Under Threat

Between 29 September and 8 October, the Russian intelligence ship Viktor Leonov operated close to Exercise Strike Warrior off the Outer Hebrides. The exercise involved around 2,000 personnel, eight ships, and 19 aircraft from six NATO countries. The Royal Navy deployed Merlin helicopters to monitor the vessel, which was not there to engage the allied fleet, but to listen and collect electronic intelligence.

Such gatherings offer intelligence vessels an opportunity to study naval communications, radar activity and the way allied forces work together.

Britain has dealt with Russian surveillance ships before. What concerns defence planners now is the amount of attention these encounters demand. Russian maritime activity near British waters rose by 25 per cent during the first seven to eight months of 2026 compared with the same period last year.

The increase comes as London tries to protect submarine communications cables and energy infrastructure while managing competing demands on its naval forces and defence budget.

A Russian Ship Watching NATO at Work

The Viktor Leonov belongs to a class of vessels built for signals intelligence. Unlike a frigate or destroyer, it is not intended primarily for combat. Its equipment is designed to detect and collect electronic emissions, including radar signals and radio communications.

NATO exercises are attractive targets for precisely that reason.

During Strike Warrior, allied ships and aircraft were operating in close coordination. Their communications, radar systems and operational routines could provide material for Russian intelligence analysts. Even where individual messages remain protected, observing patterns of electronic activity can help build a picture of how military units operate.

The Russian ship's presence also gave Moscow an opportunity to observe Britain's response.

Royal Navy Merlin helicopters were moved from Royal Naval Air Station Culdrose in Cornwall to Glasgow Prestwick airport to maintain surveillance. Such deployments reveal something about the resources Britain is prepared to commit when an intelligence vessel approaches a sensitive operating area.

There is no evidence in the available account that the Viktor Leonov obtained classified information or attempted to interfere with the exercise. Monitoring foreign military activity is not, by itself, an act of aggression.

Yet the encounter was useful to Russia simply because it forced a response.

The waters northwest of Scotland have considerable military significance. The Greenland-Iceland-United Kingdom gap has historically been a principal route for Russian naval movements into the Atlantic. Monitoring activity in this region remains important for NATO, particularly when Russian vessels operate near allied exercises.

The geography has acquired another significance in recent years. Beneath the surrounding waters lie communications and energy networks whose disruption could have consequences far beyond the military.

The Seabed Is Becoming a Security Problem

Britain's concern about Russian maritime intelligence is not confined to what happens on the surface.

Submarine fibre-optic cables carry approximately 99 per cent of intercontinental data traffic. Banks, telecommunications providers, governments and businesses depend on connections that cross thousands of kilometres of seabed.

Energy pipelines create additional points of exposure.

Protecting these networks is difficult because their routes are extensive, their locations cannot always be concealed, and continuous physical surveillance is expensive.

An intelligence-gathering operation near a naval exercise is not the same as surveying submarine cables. The activities require different equipment and serve different immediate purposes. But both can contribute to a state's knowledge of strategically important maritime areas.

Russia operates several types of vessels capable of collecting such information.

The Viktor Leonov specialises in electronic intelligence. The oceanographic vessel Yantar, operated by Russia's deep-sea research organisation GUGI, is associated with underwater research and surveying capabilities.

These ships should not be treated as interchangeable, nor does their presence establish that sabotage is being prepared. Their activities nevertheless raise questions about how much information Russia can accumulate concerning NATO's operations and the infrastructure supporting European economies.

British authorities have reasons to take the possibility of cable disruption seriously.

Incidents affecting submarine communications near the Shetland Islands in 2022 and 2025 brought attention to the vulnerability of these networks. Direct Russian responsibility was not definitively established in either case.

That uncertainty is part of the problem. Damage to underwater infrastructure may be discovered quickly, while establishing its cause and identifying those responsible can take considerably longer.

The Cost of Following Every Russian Vessel

The surveillance operation near Scotland was only one part of a busy October for the Royal Navy.

From 1 to 14 October, HMS Dauntless, a Type 45 destroyer, and the patrol ship HMS Tyne followed the Russian frigate Neustrashimy as it escorted sanctioned cargo vessels through the English Channel.

A second group required attention between 11 and 14 October. HMS Tyne, supported by a Wildcat helicopter, tracked the Russian landing ship Aleksandr Shabalin, the cargo vessel MV Energy-2 and the tug Proton as they travelled towards the Baltic Sea.

An RAF Protector RG1 surveillance drone also spent more than ten hours monitoring foreign vessels during the period.

These operations illustrate a familiar difficulty for naval commanders. Russian ships do not need to threaten British territory directly to occupy British military resources.

A destroyer assigned to shadow another vessel must devote time, fuel and personnel to that task. Helicopters require maintenance and supporting crews. Patrol ships can undertake surveillance duties, but they cannot replace every capability of a larger warship.

The strain becomes more significant when several Russian groups are moving through different areas at once.

Britain cannot simply ignore these movements. Monitoring allows the Navy to establish where foreign vessels are, observe their behaviour and respond if necessary. Yet maintaining that coverage has a cost, particularly when the same ships and aircraft have other responsibilities.

The commercial dimension adds complications.

Russian naval escorts accompanying sanctioned cargo vessels create situations in which ordinary maritime transit overlaps with economic restrictions and military surveillance. The presence of cargo ships or tugs does not prove covert activity, but it makes the wider maritime picture harder to assess.

For Britain, distinguishing routine traffic from a potential security concern requires constant attention.

And Russia can continue generating that demand without deploying a large combat fleet.

London's Expensive Answer to an Underwater Threat

The British government has begun investing in a different approach to North Atlantic security.

Its £1.5 billion Atlantic Bastion programme, funded over four years, is intended to develop a hybrid fleet capable of supporting maritime surveillance and defence. Another £330 million has been allocated to protecting seabed infrastructure.

Specialised vessels, including RFA Proteus, are part of Britain's effort to improve its ability to operate around critical underwater networks.

The spending recognises that conventional naval patrols cannot provide comprehensive protection for submarine cables.

Warships remain necessary when foreign military vessels enter sensitive areas. But a frigate following a Russian intelligence ship cannot simultaneously inspect or monitor every potentially vulnerable section of seabed.

The government is therefore investing in capabilities intended to improve surveillance and make better use of existing naval resources.

This is a significant change in what maritime defence is expected to accomplish.

For decades, naval planning has concentrated heavily on the ability to deploy warships, control sea routes and respond to hostile forces. Those responsibilities remain. Increasingly, however, governments must also consider how to protect the commercial infrastructure that supports their economies during periods when no formal military conflict is taking place.

The investment creates opportunities for British defence technology companies and shipbuilders. It also creates additional commitments for a defence establishment already facing pressure over resources.

Buying new systems is only the beginning. They must be operated, maintained and integrated with the Royal Navy's existing ships, aircraft and surveillance arrangements.

Can Britain Afford Permanent Vigilance?

London is pursuing legal measures alongside its naval investments.

Proposals before Parliament would allow prison sentences of up to 14 years and unlimited fines for malicious damage to submarine cables. Telecommunications operators would also face stronger requirements to protect critical infrastructure.

The proposals could strengthen Britain's ability to punish deliberate interference and require companies to improve their precautions.

They do not resolve the practical difficulties of detecting activity beneath the sea or proving who caused damage.

Nor can legislation substitute for naval capacity.

That question leads back to Britain's unresolved defence spending debate.

Defence Secretary John Healey has declined to make a firm commitment to raising military expenditure to 3 per cent of GDP by 2030. Instead, he has said the government would “look to” reach that level, without setting a binding timetable.

The distinction leaves uncertainty for planners responsible for long-term equipment programmes.

The Royal Navy must continue its existing missions while adapting to a growing requirement for maritime surveillance and seabed protection. New capabilities may eventually reduce the burden on conventional warships, but they also require sustained investment.

Meanwhile, Russian activity is already increasing.

The 25 per cent rise in maritime movements does not establish that Moscow has launched a coordinated campaign against British submarine infrastructure. Nor does every Russian naval transit represent a hostile operation.

What the figures do show is that Britain is spending more operational effort watching Russian vessels at a time when its maritime security responsibilities are expanding.

The Viktor Leonov has left the waters off Scotland, and Exercise Strike Warrior has ended. The Royal Navy's surveillance responsibilities have not.