The UK's critical undersea cables, worth £65bn and carrying over 90% of the nation's daily internet traffic, are set to receive a new layer of protection through the development of underwater microphones by defence firm BAE Systems. These vibration-detecting sensors, known as distributed acoustic sensing (DAS), are being adapted for military use to detect oncoming threats and shield the cables from sabotage by Russia and other hostile states.
BAE Systems Develops Vibration Sensors for Cable Defence
Experts at BAE Systems are developing these sensors to attach to fibre optic cables, turning them into a 'continuous array of microphones' that can detect vibrations on the seabed, from environmental shifts to vessel movements and marine life. The technology is currently in its experimentation phase, with data being fed from a DAS sensor on a cable into BAE's AI and machine learning programmes.
Tim O'Neill, Subsea Intelligence lead at BAE Systems, highlighted the growing threat: 'Much of our life as we know it goes through cables. There has been a real increase in the threat to this undersea infrastructure. It is no longer just benign accidents.'
Rising Threats from Russia and Other States
Cables have long faced accidental disruption from ships dragging anchors or fishermen trawling the seabed, but now hostile states are actively targeting them. Just last week, Nato forces foiled a Russian subsea sabotage plot in Arctic waters, chasing away ships training to attack cables with an undisclosed secret weapon. Defence Secretary John Healey warned in Parliament last year that Russia was 'gathering intelligence and mapping' the UK's cable network.
O'Neill explained how the DAS technology would work in practice: 'You will get an alert that something has hit the seabed at this position on the cable. DAS will be able to pick up that anchor dragging far enough away that you can tell the vessel to stop, or if that doesn't work, you still have time to send out military assets to intercept it.'
Data Challenge and Military Potential
One of the key challenges is handling the vast amount of data generated. BAE estimates that a single DAS unit can produce up to a petabyte of data per day, equivalent to streaming 57 continuous years of high-definition video. Tools are being developed to identify signals of interest as they appear and alert operators.
Alessio Patalano, who specialises in critical undersea infrastructure at King's College's War Studies Department, believes the sensors could be a 'small revolution' in underwater defence. He said: 'The sensors provide persistent and consistent data on how to understand what's happening around the cable in a way that was impossible. It makes the seabed slightly more transparent, making it easier to understand where to operate, how to operate, and against whom you are operating. It will also improve the ability to recover from any interference with the cables, because you are going to be faster at identifying where the problem is and the best way to address it.'
O'Neill added: 'The reality is that this is a state problem. If we can get this into the hands of the UK government to support their activity, trying to counter Russian threats, then we want to be part of that.' The Ministry of Defence has been approached for comment.
