Cross-Party Inquiry Examines Threats to Undersea UK Internet Cables

The Joint Committee on the National Security Strategy (JCNSS) has launched a new UK inquiry that will see cross-party MPs and Lords examine the growing threats to undersea fibre optic cables, which are described as being the ‘backbone’ of the world’s internet (broadband, mobile etc.) systems.

The inquiry, which is simply titled ‘Undersea Cables‘, notes how over 500 cables carry around 95% of all international data, with demand set to increase in the coming years. Around 60 of those cables connect the United Kingdom to the outside world, although there are also various Microwave (wireless) and satellite links, but those cannot directly replace all of the undersea fibres (particularly on longer links, such as to the USA etc.).

However, damage to submarine cables is not uncommon, with an average of 150 to 200 faults occurring globally each year and requiring about three cable repairs per week, according to the ICPC (here). In addition, it usually takes a few weeks to fix a break, but this depends upon the type of break, its depth, weather conditions and various other factors. Suffice to say that there are some well-known vulnerabilities with this infrastructure.

Most cable breaks occur due to accidents by deep sea fishing trawlers, as well as ships accidentally dragging their anchor over them, abrasion, equipment failure or marine life deciding to take a nibble (the latter is only really an issue for smaller / older cables that haven’t been buried). But in recent months the threat of deliberate sabotage has also become a much more real concern (example).

Existing responses to such damage tend to focus more on repairs because monitoring the long, and often very remote (as well as deep), cables is an extremely difficult and costly thing to do. But the inquiry group warns that the potential impact from simultaneous damage to multiple cables “would be significant, particularly during periods of heightened tension or conflict“. In that case, on-shore cable landing stations may also be targeted.

James Ovel, COO at Zayo Europe, told ISPreview:

“2024 saw several sabotage attempts targeting critical subsea cables in the Red Sea and French infrastructure in the run up to the Olympics. Even without deliberate damage, subsea cables are under threat from a large range of risks, including natural disasters and accidental cable interference. Repairs are no easy task either, given their inherent inaccessibility.

This is why the UK government launching an inquiry into UK subsea internet cables is a crucial step to further heighten the security of critical infrastructure that acts as the backbone for a connected Britain.

Creating and maintaining a diverse network of cable routes is essential for building resilient global communications infrastructure. Where possible, we always recommend investing in at least three or four distinct routes for data transmission, guaranteeing reliable connectivity in the event of one route being compromised. Creating this level of network diversity is the best way to safeguard critical infrastructure connecting the UK with the rest of the world.”

The new inquiry will thus “explore the UK’s ability to defend our subsea infrastructure, and how this might change in the coming years as technology develops“. The inquiry will look at UK strategy, engagement with allies and partners, options for improving deterrence and redress, and the adequacy of cross-Government co-ordination. It will also examine the UK’s resilience in the event of major disruption to internet infrastructure.

Chair comment:

“Our internet relies on undersea cables: around 99% of our data goes through them, connecting the UK to the outside world.

As the geopolitical environment worsens, foreign states are seeking asymmetric ways to hold us at risk. Our internet cable network looks like an increasingly vulnerable soft underbelly.

There is no need for panic—we have a good degree of resilience, and awareness of the challenge is growing. But we must be clear-eyed about the risks and consequences: an attack of this nature would hit us hard. Our inquiry will look at what’s needed to defend our subsea cables, and consider the UK’s national resilience should our internet face major disruption”.

However, it’s worth remembering that cutting lots of transatlantic fibre optic cables within the same short period of time, while a risk, is something that would be difficult to completely prevent and also to carry out. On the other hand, the more such attacks take place, the greater the strain on limited resources for repairs, which could result in a build-up of cumulative delays and thus connectivity problems.

The same sort of attack could similarly then be used against an aggressor. The fact that so much international trade is carried over the internet also means that other countries are likely to be harmed by such an activity, which in a conflict may also include the attacking state or its allies (i.e. directly or indirectly).

The inquiry itself will be open for submissions until Thursday 6th March 2025.