How vulnerable is the UK to undersea cable attacks?

• Inquiry: Undersea cables
• National Security Strategy (Joint Committee)

Undersea fibre-optic cables are the ‘backbone’ of the world’s internet system, underpinning global commerce and communications. Over 500 cables carry around 95% of all international data, with demand set to increase in coming years.

These cables are often long and remote, making them difficult and costly to monitor. They are vulnerable to natural events, accidental damage by vessels or deliberate sabotage.

Around 60 cables connect the UK to the outside world. This provides reasonable resilience if one is damaged—but the impact of simultaneous damage to multiple cables would be significant, particularly during periods of heightened tension or conflict. On-shore cable landing stations may also be targeted.

Although the Government has taken steps to improve maritime security in recent years, concern is growing about both the capability and intent of hostile states. Defence Secretary John Healey told MPs last week that the UK was monitoring Russian spy ship Yantar, which he said was mapping critical underwater infrastructure.

A number of cables in northern European waters – including those providing links between Norway, Sweden, Finland, Estonia and the Shetland Islands – have been severed over the past few years. Over 50 Russian vessels have been observed around areas of high cable density in the Baltic Sea. Further afield, concerns have been raised about Chinese sabotage—particularly around Taiwan.

The inquiry will 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.

Full terms of reference are available on the Committee’s website. Submissions can be made via the Committee’s website until 11.59pm on 6 March.

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”.

Further information

• About Parliament: Select committee
• Visiting Parliament: Watch committees

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