Call for Evidence

Summary

Undersea fibre-optic cables carry the internet data which underpins global commerce and communications. The UK has around 60 undersea cables carrying 99% of our data connecting us to the outside world. Demand for capacity is set to increase in future.[1]

Undersea cables can be damaged by natural events, accidents, or deliberate severing. The number of UK cables provides reasonable resilience, though the impacts of simultaneous damage to multiple cables or on-shore infrastructure could be significant.[2] There have been numerous incidents in recent years.[3]

Although the Government has taken a number of steps to improve maritime security, alongside Allies and partners,[4] concern has been growing over Russian and Chinese capabilities to hold undersea infrastructure at risk - particularly during periods of heightened tension or conflict.[5]

This inquiry will examine the UK’s ability to protect undersea cable infrastructure from threats (including shore-based connections), and the adequacy of national resilience in the event of major and protracted disruption. It will seek evidence on military capabilities, trends in subsea technologies, and co-ordination across Government and international partners. It will further examine choices in the context of limited resources, for example the balance between enhancing domestic resilience, and improving detection and interdiction. The inquiry will also look at how Government reviews, such as the Strategic Defence Review and the Resilience Review, should account for undersea cables.

Terms of reference

The Committee is seeking evidence on the following questions (there is no requirement to answer all questions in your submission) by 23:59 on Thursday 13 March:

1. How might the UK’s reliance on undersea cables evolve over the next 10-15 years?

• What are the key vulnerabilities at the moment and how might these change? (Including both undersea infrastructure and on-shore cable landing stations).
• How does this compare to the situation in other countries (particularly island states)?
• Are there any long-term alternatives to undersea cable infrastructure?

2. Who are the main threat actors and what are their capabilities?

3. What developments are expected in subsea technologies over the next 10 years?

• Do these favour aggressors or defenders?
• How well positioned is the UK to take advantage?

4. How resilient are the UK public and private sectors likely to be in the event of major disruption?

• Which sectors would be most affected?
• What would be the immediate and long-term implications?
• What might be the constraints on restoring connectivity swiftly?

5. How effective are the deterrents against the targeting of our undersea cables? Are any improvements needed regarding:

• maritime security capabilities;
• military strategy;
• engagements with Allies and partners;
• legal frameworks, including options for redress?

6. How well is policy and co-ordination working across Whitehall departments, law enforcement and private sector actors? Are any changes needed?

7. In the context of limited resources, what is the appropriate balance to strike between enhancing domestic resilience on the one hand, and improving detection and interdiction on the other?

• How should these be accounted for in the Strategic Defence Review, and the Resilience Review?

This is a public call for evidence. Please bring it to the attention of other groups and individuals who may not have received a copy directly.

[1] Policy Exchange, From Space to Seabed (2024)

[2] HMG, National Risk Register (2025)

[3] The Economist, Finland’s seizure of a tanker shows how to fight Russian sabotage (2024)

[4] See for example HMG, Joint Maritime Security Centre; Royal Navy, UK protection enhanced (2023); HMG, Joint Expeditionary Force activates UK-led reaction system to track threats to undersea infrastructure (January 2025); European Commission, EU-NATO Task Force on the Resilience of Critical Infrastructure (2023); NATO, NATO launches Baltic Sentry (January 2025)

[5] French Ministry of Armed Forces, Seabed Warfare Strategy (2022); RUSI, Stalking the seabed (2023); CSIS, Safeguarding Subsea Cables (August 2024)