Britain risks losing its maritime advantage to Russia due to the growing threat of its submarine fleet, the First Sea Lord has said.

General Sir Gwyn Jenkins outlined the threat facing the UK and its Nato allies during the Sea Power Conference (December 8). This comes as the first phase of a technological advancement drive, Atlantic Bastion, was revealed in Portsmouth to showcase what new systems will be used to track Moscow’s submersibles.

Pictured: 08/12/2025 - First Sea Lord, General Sir Gwyn Jenkins KCB OBE RM delivering his Keynote Speech at the First Sea Lord's Sea Power Conference 2025. | UK MOD Crown copyright

placeholder image — Pictured: 08/12/2025 - First Sea Lord, General Sir Gwyn Jenkins KCB OBE RM delivering his Keynote Speech at the First Sea Lord's Sea Power Conference 2025. | UK MOD Crown copyright

The First Sea Lord said the world is becoming more dangerous and unstable due to the rise in authoritarian regimes. “Just look at Russia,” he added. “Despite the millions of lives and the cost of their egregious illegal invasion of Ukraine, they continue to invest billions in their maritime capabilities, particularly in their Northern Fleet, a 30 per cent increase in Russian incursion in our waters just in the last two years.

“It’s most visibly seen in the presence of their spy ships like the Yantar. But I can tell you today, the Yantar is only the visible bit you see in the public and it’s not the bit that worries me the most. It’s what’s going on under the waves that most concerns me.

“I can also tell you today that the advantage that we have enjoyed in the Atlantic since the end of the Second World War is at risk. We are holding on, but not by much. There is no room for complacency. Our would be opponents are investing billions.

“We have to step up, or we will lose that advantage. We cannot let that happen, as the Secretary of State for Defence said recently in his message direct to Putin, we see you and we know what you are doing.”

Sir Gwyn said Britain will continue to be Nato first and support its allies, with HMS Prince of Wales deployment this year showcasing the Royal Navy’s capabilities and commitment to the freedom of navigation. He added that since the UK relies on free flowing trade and its undersea infrastructure needs protecting.

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Sir Gwyn describes the latter as a lifeline for both the UK and Nato. Alongside a fresh defensive pact with Norway, the UK is aiming to produce various autonomous capabilities to track Russian submarines alongside conventional warships. Other programmes include Atlantic Shield, which focuses on air defence in the north, and Atlantic Strike which is an offensive programme against any aggressors.

Sir Gwyn added that unnecessary processes have been cut in the Royal Navy over the past 100 days, freeing up sailors for an extra 200,000 hours. “This is a call for action,” he told the conference. “We are moving out because we have no choice.

“The alternative is not worth thinking about. Our job is to be ready, and I want you to join us on that journey. I can’t promise it’s going to be easy. It’s not. We will face headwinds, we will face rough seas, but together, we can solve these problems if we have the appetite, if we have the determination, and if we have the mindset.”