Ruskii
Russian submarine followed spy ship into British waters
A newly declassified image of the encounter has been released to The Sunday Times
Saturday December 27 2025, 9.30pm GMT, The Sunday Times
Russian submarines are secretly being deployed alongside Moscow’s best-known spy ship to map critical undersea infrastructure around Britain, raising fears of potential sabotage.
Defence sources have revealed that in November last year a submarine shadowed the Yantar, a Russian vessel officially described as a research ship, as it surveyed a gas pipeline linking Britain and Ireland.
It is not known whether the escort was one of Russia’s purpose-built sabotage submarines. In response, the Royal Navy tracked the Yantar with one of its own submarines.
A newly declassified image of the encounter has been released to The Sunday Times, showing the navy’s submarine and an anti-submarine Merlin Mk2 helicopter during the incident in the Irish Sea.
It is believed to be one of several operations where Russian submarines have secretly accompanied the Yantar into waters close to the British Isles.
Last week the head of the Royal Navy, General Sir Gwyn Jenkins, warned that Russia was renewing investment in its elite deep-sea submarine division, known as GUGI, giving Moscow the option to use “physical action” against the UK and its western allies.
General Sir Gwyn Jenkins
ROYAL NAVY
Before the incident in November 2024, the Yantar was placed under close surveillance after it left Russia’s Kola peninsula, sailed towards Norway, down the Channel and into the Irish Sea towards the Isle of Man. It briefly activated its transponder while loitering close to an area where the gas connector is exposed.
Naval vessels and patrol aircraft tasked with tracking the Yantar’s movements were required to adopt countermeasures, defence sources said. Crews were prohibited from using mobile phones and instructed to restrict transmissions to secure channels in order to reduce the risk of interception.
A navy hunter-killer submarine was ordered to surface near the spy ship in a show of force. Sources revealed that it sent the following transmission when it surfaced: “Thank you for allowing us to monitor your every move for the last few days.”
The Yantar being tracked in UK waters by RFA Proteus in January
MOD
HMS Anson is the Royal Navy’s latest Astute class hunter-killer submarine
BAE SYSTEMS/PA
The gas pipeline was later inspected by specialist divers to ensure it had not been mined. There are fears that Russia could plant explosives or charges on underwater cables or pipelines, which could be detonated during a time of war.
The involvement of a navy submarine in the counter-operation was revealed by John Healey, the UK defence secretary, in January. However, the presence of a Russian submarine during this encounter had been kept secret until now.
Senior British defence sources said Russia may be intensifying so-called grey-zone operations in waters around Britain and Ireland because it is being pushed out of the Mediterranean and now the Baltic Sea — the latter due to Finland and Sweden’s accession to Nato.
UK armed forces are also worried that Russia is attempting to exploit Ireland’s military neutrality — it is not in Nato and is one of the lowest defence spenders in Europe — to expand its footprint close to the UK. Three senior British figures said independently of one another that Ireland was seen as the “soft underbelly”.
President Putin visiting Russia’s largest shipbuilding plant in July
GETTY IMAGES
Maritime patrols in the Irish Sea have increased sharply this year after Russia began mapping out the precise location of gas, electricity and fibre optic cables that criss-cross the seas. Although no subsea cable has been damaged, intelligence indicates Russia has made plans to sabotage them at points where they are vulnerable.
Intelligence services have received reports suggesting that fishermen in Wexford, southeast Ireland, have been offered money to drag metal-cutting objects across the sea floor at specific co-ordinates.
Russia is interested in asserting its presence around Britain’s submarine fleet, which operates from Faslane in northwest Scotland. Its shipyards for submarine construction are in Barrow-in-Furness in Cumbria. Britain’s four new dreadnought submarines, which will carry the nuclear deterrent, and the recently announced fleet of 12 SSN hunter-killer submarines — part of the Aukus submarine pact with the US and Australia — are being built by BAE at the Barrow shipyards.
In addition to the potential use for sabotage, European military officials believe the Yantar and other spy ships are being deployed in the Irish Sea to intercept the communications of naval ships and aircraft and better understand how Nato and its allies respond to provocations. Its intelligence-gathering capabilities also make it difficult to monitor the vessel without risking the compromise of sensitive communications.
• How Putin’s spy ships are ushering in a new era of marine sabotage
“We were aware of its planned arrival long before it entered our area of responsibility,” a senior Irish military intelligence officer said. “Once it crossed into Irish waters, however, we observed a change in crew behaviour and the mounting of weapons. The Irish navy and air corps maintained constant surveillance with our partners.”
Although the Yantar is capable of underwater sabotage, defence sources said they were confident that it did not deploy submersibles from its “moon pool” — a launch facility beneath the ship — while loitering above the pipeline.
The Irish government was later warned that sabotage of the gas interconnector during winter months could cause rolling blackouts, leading to severe economic damage.
“There is deep co-operation with EU member states and with the United Kingdom in respect of all of these issues, and that has been ongoing,” Micheál Martin, the prime minister, told The Sunday Times.
Micheál Martin
JOHN MACDOUGAL-POOL/GETTY IMAGES
“One has to be very vigilant and one has to strengthen resilience in respect of critical undersea infrastructure because our society and modern economy depend on that.”
Martin pointed to sabotage attacks believed to have been orchestrated by Russia against subsea cables in the Baltic Sea and physical attacks in Poland and other EU states. “There is an increase in hybrid attacks of different types, some involving arson and others hiring low-level criminals to do damage. Europe is on increased alert and it’s obviously related to the war,” he said.
It is believed Russia has mapped the routes and landing points of key transatlantic cables. In one incident, men attempting to access a cable landing point via a manhole were later identified as Russian nationals.
Russian special services have also been observed on the west coast of Ireland, possibly receiving signals from submarines which surfaced at sea.
Russia’s underwater operations are directed by GUGI, its directorate of deep-sea research, which the UK sanctioned last June. It operates a fleet of about 50 specialist vessels.
Aaron Amick, a retired US navy sonar operator, said Russia had developed a range of large and small submarines capable of interfering with undersea cables. Some, such as the Belgorod, can deploy the deep-diving mini-submarine Losharik, designed to operate on the seabed. Others are under construction, including Sergei Bavilin, a next-generation deep-ocean submersible capable of diving to depths of 11,000 metres.
The Ministry of Defence said: “As the defence secretary has said, our message to President Putin is clear: we see you, we know what you are doing, and we will not shy away from robust action to protect this country. We are acutely aware of the threat posed by Russia, including attempts to map undersea cables, networks and pipelines belonging to the UK and our allies, and we are tackling these threats head on.
“That is why the prime minister has set out the biggest sustained increase in defence spending since the Cold War, including a commitment to raise spending to 2.5 per cent of GDP from April 2027, with an ambition to reach 3 per cent in the next parliament, as economic and fiscal conditions allow.”
Sir Keir Starmer’s government has also established a cross-government body to coordinate policy on subsea cables, following a report by the Joint Committee on the National Security Strategy (JCNSS). The Undersea Infrastructure Security Oversight Board, chaired by the Cabinet Office, will set strategic direction.
In its response to the committee’s report, Subsea telecommunications cables: resilience and crisis preparedness, the government agreed to update risk planning to cover co-ordinated sabotage of Britain’s transatlantic and European connections. It is also exploring options to acquire a sovereign repair ship to respond to cable damage during a security crisis.
Matt Western, chairman of the JCNSS, welcomed the steps but said preparations might lag behind the threat. “The security situation with Russia could worsen faster than our ability to prepare industry and the military,” he said. “Once-unthinkable events are becoming more likely. We must move quickly.”