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How vulnerable are the UK’s undersea cables? JCNSS publishes written evidence

29 April 2025

Today the Joint Committee on the National Security Strategy has published written evidence to its inquiry into undersea cables.

The Committee is investigating how well the UK is able to defend its undersea infrastructure, including the fibre optic cables that carry vast amounts of data between countries.

These cables are often long, remote and costly to monitor, leaving them vulnerable to damage by natural events, shipping or even deliberate sabotage.

Several submissions highlight efforts by states like Russia and China to develop the ability to attack subsea cables. Some submissions suggest that an increase in international tensions could see adversaries like Russia launch attacks on multiple parts of the network.

Much internet content is stored in the UK’s regional datacentres, submissions say, reducing reliance on undersea cables. However, damaged cables could disrupt sectors requiring urgent or time-sensitive information such as finance, defence, news and government services.

The evidence is published on the Committee’s website.

Further information

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