Subsea Telecommunications Cables: Resilience and Crisis Preparedness

Julian Lewis Excerpts

Thursday 8th January 2026 Commons Chamber

[Matt Western (Warwick and Leamington) (Lab)]

It is a pleasure to present the first report of this Parliament of the Joint Committee on the National Security Strategy. I thank the Backbench Business Committee for granting time for this statement on the United Kingdom’s resilience and crisis preparedness in relation to subsea telecommunication cables.

Subsea cables are critical to the UK’s economic prosperity and global influence. They provide crucial, irreplaceable connectivity between the United Kingdom and the rest of the world. Like the trade routes of old, they are the arteries and veins of global commerce and communication. They carry a staggering 99% of the United Kingdom’s international data, and $1.5 trillion-worth in global cross-border trading. That is across 64 cables, including 45 international connections, but capacity is concentrated in newer equipment. For example, two newer cables carry 75% of transatlantic capacity.

For centuries, the United Kingdom has felt secure as an island, but that geostrategic strength is now a vulnerability, as the subsea cables on which the world depends have become a new front in a hybrid war. Revisionist powers and their proxies are targeting liberal democracies’ critical underwater infrastructure. Their aim is to disrupt connectivity, inflict economic damage and cause panic. By attacking us in this way, below the threshold of war, our adversaries are demonstrating their ability to do more at a much bigger scale and a much faster rate, should hostilities escalate. Subsea cables can be cut by something as unsophisticated as a rogue anchor dragged along the seabed by a commercial vessel.

As we have seen over recent months in the Baltic sea, such activity can easily be made to look accidental and readily denied, but Russia and China are also developing more targeted capabilities and operating at greater depths in our oceans, where the cables are harder to access and repair. Governance of subsea cables has been fragmented across at least eight Departments, seven agencies and numerous private sector actors. Contingency planning has been inadequate and largely ignored the possibility of a co-ordinated attack. We rely on legislation from 1885, with the threat of a paltry £100 fine to deter acts of cable damage.

The United Kingdom’s approach to subsea cables is no longer good enough. Concerned by the apparent lack of action in this area, my Committee launched an inquiry to assess the resilience of the United Kingdom’s subsea telecommunications cable network and the effectiveness of the Government’s work to protect it. We spoke in public and in private to security experts, lawyers, cable owners and operators, cable repair firms, former and serving naval leaders, policymakers from NATO allies, telecoms firms and those working in sectors reliant on data carried by subsea cables.

We were encouraged to find that, in the business-as-usual scenario, the UK subsea cable network enjoys a good level of resilience. Nevertheless, there are points of vulnerability in the network and gaps in the Government’s work, such as onshore infrastructure. Cables come ashore via landing stations, which remain vulnerable to sabotage. Many onward terrestrial links converge towards data centres. This all presents risks for low-level deniable attacks, which would be costly, provocative and hard to prevent.

Another example is the lack of genuinely sovereign repair capabilities. The United Kingdom is currently reliant on cable maintenance and repair consortiums, but repairs can take many days or weeks, and there is no guarantee that these consortium ships will be available when we need them. Commissioning a cable repair ship does not happen overnight. There is little to no redundant repair capacity that could be purchased at short notice on the open market. The Government must look ahead and acquire a genuinely sovereign cable repair ship by 2030.

Our report covered many other issues, and we were encouraged by the Government response. They had clearly engaged with the issues in depth, and there was a clear explanation of their rationale on each of our points. In particular, we are glad that the Government have committed to, first, establishing an oversight board, chaired by the Cabinet Office, to co-ordinate cross-Government work on protecting undersea infrastructure; secondly, updating impact assessments and strengthening contingency planning across critical public and private sectors; and thirdly, writing to landing station operators to emphasise the importance of robust security standards, and to ask them to produce emergency repair plans within 12 months.

None the less, the Government response does not address the Committee’s concerns about developing a more robust military deterrent. The recent announcement of further details of the Atlantic Bastion programme is welcome, but the capabilities outlined must be deployed at sufficient scale and pace to effectively deter threats to subsea cables. Furthermore, our Navy may be world-renowned, but our hands are tied by international law when it comes to intercepting suspect civilian ships outside our territorial waters.

The Government have said that they are launching a comprehensive review of legislation relating to subsea cable infrastructure, but they have not elaborated in detail. They have committed to exploring options for a sovereign cable repair ship, and we will keep a close eye on the progress made on this key recommendation. We will also keep a close eye on the commitments to upgrade security at cable landing stations, on which the Government have agreed to make progress.

Of course, the damage that our adversaries can cause us is not without limitation. Cable-monitoring schemes are increasing, and NATO can track sub-surface activity closely in a crisis. Would-be saboteurs may be identified by the security services in advance of carrying out an attack, but the damage that our adversaries can cause is nevertheless extensive. Unless we adopt much better mitigations, a tipping-point scenario seems possible. From the evidence submitted to our inquiry, we estimate that severe disruption would include financial payment and supply chain failures, degraded communications, overstretched emergency responses and unexpected cascading issues, all at a time of crisis.

We hope that this report has given the Government the wake-up call that they need to take this matter seriously. We will keep a keen eye on the Government’s progress in these areas, and we will conduct further scrutiny as required.

[Sir Julian Lewis (New Forest East) (Con)]

I congratulate the Committee on its report, and I know that it took evidence from authoritative experts, such as the excellent Elisabeth Braw. Can the Chair explain to the House whether his findings were compatible with the alarming headline in today’s Daily Mail about another report from the Council on Geostrategy think-tank, which claims that cutting just 60 cables going in and out of the UK could affect 99% of our data? Is there more resilience in the system than that would seem to suggest?

[Matt Western]

I thank the right hon. Gentleman for his service on the Committee over so many years, which was hugely valued, and his point is absolutely fair. I have not seen the specific report that was published today, but it echoes the points that we have made in this report. We do not want to be alarmist, but we cannot accept any complacency about what the threats are, because there is a genuine risk.

The truth is that there is the potential to reroute cables. There is a significant amount of traffic across the Atlantic—some of it comes into Ireland, some of it into mainland Europe, and some of it into the UK—so it is always possible for data communications to come through to us in different ways and, in an extreme crisis, for us to turn to satellites, although that capacity is significantly lower. I am sure there are some very valid points in that report, and I will look at it more closely.