Fears of escalation towards World War 3 intensified yesterday after the head of the Royal Navy issued a stark warning that Russia is preparing to deploy elite deep-sea submersibles capable of sabotaging critical British undersea infrastructure.

General Sir Gwyn Jenkins, the First Sea Lord, revealed that Moscow has renewed investment in its secretive Main Directorate of Deep-Sea Research (GUGI). This specialist unit is blamed for mapping and potentially disrupting the seabed cables and pipelines vital to the UK’s economy and national security.

Speaking with the Financial Times, Sir Gwyn said: “We’ve seen GUGI’s subsurface capabilities restarting.

“We know that they’ve had some issues with that programme. It appears that they have reset that programme. So we’re expecting them to deploy again.”

He added: “That gives Moscow the option for physical action, if they want it.”

The alert comes amid soaring tensions between the West and Russia over the war in Ukraine. Experts fear that attacks on undersea assets represent a dangerous new front in “hybrid warfare” — actions that fall short of full-scale conflict but carry potentially catastrophic consequences.

The United Kingdom relies almost entirely on a network of subsea fibre-optic cables for international data transmission. These lines carry over 95% of global internet traffic and facilitate trillions in daily financial transactions, underpinning everything from emergency services and banking to military coordination.

Past warnings have highlighted the devastating impact of disruption. Severing key cables could cause widespread blackouts, paralyse global markets, and isolate the UK digitally for weeks or even months, leading to economic chaos costing billions.

Recently, damage to Baltic and North Sea cables has been linked to Russian naval movements.

Despite the heavy financial toll of the Ukraine war, Sir Gwyn noted that Moscow’s investment in GUGI is “improving all the time.” The programme had been set back by a 2019 fire on the Losharik submarine which killed 14 officers, but that lull appears to be over.

In response, the Royal Navy is advancing “Atlantic Bastion,” a multi-million-pound defensive initiative. This defensive framework utilises advanced sensors, autonomous underwater vessels, and a strategic pact with Norway to guard the GIUK gap — the naval chokepoint between Greenland, Iceland, and the UK.

The UK’s Defence Secretary, John Healey, stated: “We are living in a new era of threat which is less predictable and more dangerous…They are mapping our undersea cables.”

Sir Gwyn concluded with a warning regarding the UK’s geography.

He said: “We effectively do have a border with Russia. It’s the open seas to our north…The comfort that we take from being an island…is a false comfort.”

As intelligence chiefs highlight Russian “grey zone” sabotage across Europe, these warnings fuel fears that seabed aggression could become the spark for a wider global conflict.

The Atlantic Bastion initiative explains how the UK plans to maintain its naval advantage and protect subsea infrastructure in the face of modernising Russian capabilities.