UK should have more submarines, MPs told

The UK should consider significantly expanding its submarine force as undersea threats proliferate and the barriers to entry for hostile actors continue to fall, witnesses told MPs during a House of Commons Defence Committee session on undersea activity.

Brett Phaneuf, founder and chief executive of Submergence Group LLC in the United States and M Subs Ltd in the UK, argued that submarines remain central to deterrence and should be treated as a national strategic priority.

“We should have 100% more submarines,” he told the committee. “The advent of uncrewed and/or autonomous systems will be helpful in defraying some of the cost and delays in building submarines by having a capability that works in concert with them.”

Phaneuf warned that the rapid spread of uncrewed underwater technology is changing the character of the undersea domain, with cheap systems increasingly capable of harassing shipping, disrupting trade and threatening critical infrastructure.

“We are seeing a lot more people get into the sea at a lower cost of entry using a panoply of uncrewed systems, microelectronics and acoustics technology,” he said. “The undersea domain in uncrewed systems is catching up with the microelectronics explosion in the 1990s and early aughts.”

He added that the strategic value of these technologies is no longer limited to major powers, arguing that even small states now have access to capabilities that were previously out of reach.

“It is a certain proliferation. I think the most obvious example of all that is what is happening in the Black Sea,” he said, describing the use of sophisticated systems to challenge traditional naval forces. Phaneuf said the use of commercially sourced components and open supply chains has further accelerated the pace of proliferation, with hostile actors able to acquire equipment through mainstream online marketplaces. “These technologies are proliferating; we have seen similar very low-tech capabilities in Yemen, put together with parts that are brought in hardware stores and on Amazon, eBay, or Alibaba,” he told MPs. “That is frightening.”

He argued that such systems may not pose an existential military threat in themselves, but can generate strategic impact by disrupting trade and forcing costly defensive responses. “Those are not going to overall threaten the nation; those are things that will harass and weaken us through abatement of trade,” he said. “Our key adversaries have been very rapidly developing a considerable mass or number of extremely sophisticated capital assets, both crewed and uncrewed, that we are going to find hard to match in Europe or in the United States in the near term.”

Professor Peter Roberts, Associate Fellow at the Centre for Public Understanding of Defence and Security at the University of Exeter, said the proliferation of undersea capabilities is now becoming increasingly widespread and difficult to contain.

“Yes, there is proliferation, yet it is quite localised and very contextual,” Roberts told MPs. “We are now seeing the Taiwanese, the Indonesians, the Filipinos, everyone’s trying to get into this game.”

He said the increasing availability of systems and components means states can acquire equipment quickly, but often struggle to integrate it effectively into a coherent capability.

“It is about the concept of operations, because you can buy all the stuff you want and you can field it, but if you cannot marry it together and use it effectively, you are really pouring resources into a hole that has no use,” he said.

Roberts also warned that the undersea domain has historically been underfunded and under-appreciated, despite its importance to modern security and economic stability.

“It is an area that has been underused and under-invested in, and it is exploitable with a very low cost barrier to entry,” he told the committee. “Before, if you wanted to operate a submarine, you were talking about decades of building experience… Now, you can do it with electronics and information available on the internet.”

Commodore (Retired) John Aitken, a former Royal Navy submariner and now an underwater systems manager at Thales, said undersea infrastructure is increasingly central to global trade and therefore an attractive target for disruption.

“There has certainly been a massive increase, probably because of awareness of the importance of undersea infrastructure and the part it plays in global trade,” he said.

Aitken told MPs that activity beneath the sea is expanding rapidly, with both state and non-state actors exploiting the difficulties of detection.

“There has been an enormous increase in the numbers of people getting involved,” he said. “It is pretty unusual to get non-state actors involved in this sort of activity. But it is still really difficult to do.”