USC0023
Written evidence submitted by Indeximate Ltd
Monitoring the health and security of Undersea Infrastructure
The Challenge
The UK's digital lifeline depends on approximately 60 undersea cables that carry 99% of our international data traffic. These critical assets face increasing threats from natural events, accidents and deliberate sabotage. As global tensions rise, there is growing concern about potential hostile actions against this vital infrastructure by state actors.
1: How might the UK’s reliance on undersea cables evolve in the next 10-15 years
The call for evidence focuses largely on the risk to telecoms cables. Whilst there is clearly a significant threat to the UK economy in the loss of multiple communications cables, the authors believe that over the next 10-15 years, the REAL threat is the growing reliance on subsea power cables – both national and international.
Today, the UK currently produces around 15-20% of our electricity from offshore wind – brought ashore by power cables (with integrated fibre optic). Similarly, the UK increasingly imports 10-20% of electricity from Europe and Norway via a range of subsea interconnects. This has the potential to grow beyond Europe.
Use of both of these is going to significantly increase over the next decade (offshore wind will quadruple by the end of the decade).
Moreover, the electricity is often generated in the wrong place – typically Scotland and needs to be re-routed to population centres. Again, this is going to be achieved by an array of subsea domestic interconnects built at a significant expense to the UK economy (~£58bn).
Unlike data, power is not as easily networked – at least not at the asset level – potentially distributed though at an international level. In central Europe this is over the land based grid but for all coastal states this is by subsea power cable.
In the next 10 years a concerted effort to disrupt electricity supply could have catastrophic effects. Whilst cables DO naturally fail (around once every 600km / year) and the grid can cope with a small amount of outage, if a targeted effort was made to fail mutiple interconnectors at the same time together with those of the largest windfarms the result would be a crash situation on the grid and the need for a blackstart. Essentially power cuts throughout the country. The situation is exacerbated by the timeline for repair. Subsea power cable repairs are not as easily achieved as data cables – the logistic effort required takes typically 6 months during which time electricity could end up in a situation of rolling blackout.
The 2022 National Strategy for Maritime Security identifies the vulnerability of all of our maritime cable assets (telecoms and power) noting that 99% of our communications, $1.9tn of daily FOREX trading and £545 bn of GVA rely on them. The report notes that “A significant loss of subsea cables would be felt by everyone in the UK”. The report additionally identifies the challenges in implementing maritime security domain awareness by listing the 27 bodies with a responsibility in the area.
The EU in-depth analysis on cable vulnerability published in June 2022, goes further and focuses heavily on our dependencies on subsea cables and the risks present. NATO has additionally (in 2023) created a Critical Undersea Infrastructure Coordination cell under Lt Gen Hans-Werner Wiermann to address the issues. France has published their Seabed Warfare Strategy which focuses heavily on the threat and specifically calls for a sensing network to combat this.
Indeximate believe that the sensors required are already in place.
The power, energy and communication assets necessary for the UK function are unprotected and vulnerable. Vessels with malignant intent have a widespread freedom to manoeuvre and by turning off their AIS are relatively undetectable. Surveillance is limited and expensive. Once a location is visited, activity beneath the waves is effectively invisible.
The UK shares reliance with offshore cables with most of Northern coastal Europe. As offshore wind and a European energy grid expands, this reliance is only going to become more critical and the need for monitoring greater. A similar situation is found in Taiwan who are additionally suffering from multiple cable cuts.
2: Who are the main threat actors and what are their capabilities?
Press reporting places the evidence firmly at the door of Russian and Chinese sponsored or traceable activities.
Today we see most activity in the form of overt reconnaissance and “accidental” anchor drag from the “ghost” Russian fleet. Similar behaviour is observed in Taiwan and the Northern Baltic. This happens so often it is assumed to be a matter of directed policy.
When targeted by technology and thwarted this is likely to turn into more complex clandestine activity with subsea activity and potential lingering packages with remote activiation to achieve a parallel destruction.
3: What developments are expected in subsea technologies over the next 10 years?
The authors firmly believe that the sensors required to monitor threats are already present in the asset portolio of cables both telecomms and power – namely fibre optic sensors. A low-cost addition to a power cable at manufacturing but hard (but not impossible) to retrofit.
A key technology that has reached maturity over the last decade is Fibre Optic Sensing, this is now being applied more commonly to the needs of subsea power cabling for health monitoring but a small extension of thought and direction can lead to new uses for protection of critical national infrastructure.
This extensive network of fibre-enabled infrastructure creates an opportunity to develop a comprehensive protective monitoring system across our maritime domain. By leveraging these existing optical fibres, the U.K. can significantly expand monitoring capabilities without the need for new dedicated sensor deployments.
A transformative technology exists that could dramatically improve the security of undersea infrastructure. Distributed Acoustic Sensing (DAS) uses the optical fibres already present within undersea cables to create an extensive network of highly sensitive detectors capable of monitoring these assets in real time.
DAS technology transforms ordinary optical fibres into sophisticated sensors without any physical modification to the cables. The system works by:
This remarkable approach effectively converts hundreds of kilometres of undersea cable into a continuous sensor array, with detection points every few metres. The system can pinpoint events with exceptional accuracy, detecting disturbances such as:
What makes DAS particularly powerful is its ability to integrate with existing maritime monitoring systems. By combining DAS with Geographic Information Systems (GIS), Automatic Identification Systems (AIS), and satellite data, we can create a comprehensive defensive network capable of identifying both accidental and intentional threats to undersea infrastructure. The U.K. may have additional undersea sensing systems for national defence that might also be integrated to further enhance the sensitivity and accuracy of such a network.
In addition to the expressed utility for providing situational awareness of activity surrounding our maritime cable portfolio, the technology also has a keen advantage in the ability to detect sub-surface targets and also targets that are directly interfering with cables.
The method by which this is installed creates an opportunity for the UK. By monitoring suppliers working with asset owners to provide cable health there exists an opportunity to take and repurpose the sensing information (listening on the seabed) to look at the sea surface for vessels, the sub surface and the cable itself for signs of interference. This we envisage can be supplied to the UK as a service – obviating the need for significant hardware expenditure. This transition is already underway.
6: How well is policy and co-ordination working across Whitehall departments, law enforcement and private sector actors? Are any changes needed?
The 2022 National Strategy for Maritime Security identifies the vulnerability of our maritime cable assets (telecoms and power) noting that 99% of our communications, $1.9tn of daily FOREX trading and £545 bn of GVA rely on them. The report notes that “A significant loss of subsea cables would be felt by everyone in the UK”. The report additionally identifies the challenges in implementing maritime security domain awareness by listing the 27 bodies with a responsibility in the area.
There is a lack of clarity over which body is responsible for the security of such criticial assets, however the RN appears to hold the responsibility with the new RFA Multi Ocean Surveillance Ships and further subsea responsibility.
This situation could be clarified and any NATO liaison made explicit to ensure there is a single body directed as having responsibility for these critical maritime assets.
In addition, there is a role of the Crown Estate in licensing activities for subsea cables. The current situation is not clear other than for international connections where ICPC rules / UN Conventions prohibit the use of sensing for purposes other than cable health. If the power cables become acoustic sensors then this is clear – listening to a foreign nations soverign footprint from another country. What is less clear is where the purposes are clarified into actionable content – for example, if the sensing mechanism for cable health is “listening to the cable” you can’t stop listening to the water column – however your actions may constrain what measurements are extracted. This call for evidence is UK focussed however and the reason we mention this is because of the lack of clarity over purposes of monitoring on UK cables. We experience this in our client base where we on occasion are informed that “our licence doesn’t run to listening”. The expression of rules is unclear.
7: The Path Forward
The UK has a unique opportunity to lead in implementing technology to protect our diverse undersea infrastructure. By leveraging the optical fibres within telecommunications cables, power interconnectors, offshore wind cables and pipeline systems, an integrated defensive network with unprecedented coverage can be created.
With commercial components already available, a comprehensive detection and monitoring system can be achieved, well within the next decade, significantly enhancing maritime security posture while protecting the critical energy, data and resource connections that underpin the economy.
This approach not only addresses immediate security concerns but positions the UK as a global leader in undersea infrastructure protection — a critical capability in an increasingly interconnected world.
The authors believe that the act of sensing to monitor the health of cables can be reused to provide additional benefit in protecting critical infrastructure by listening to the environment and monitoring the activities. This affords a clear economic advantage over widespread deployment of targeted sensing (which can augment such an approach) and supports directly the aims of domestic resilience (through cable health) whilst at the same time supporting detection of threats.
This information is provided by Indeximate Ltd, a UK company dedicated to preventing failure in subsea cables. Indeximate was created in 2022 by a team of world respected sensing experts to bring change to the management of subsea cables. In addition to sensing expertise for cable health, Indeximate also brings a unique repurposing of data value proposition currently being explored by MOD for the protection of Criticial National Infrastructure.
Dr Chris Minto, Director
5 March 2025