Britain warns of catastrophic risk to undersea cables as MPs urge tougher stance on Russia

Britain’s network of undersea cables that connect the United Kingdom with the world faces the risk of a catastrophic attack, MPs warned in a report released Thursday. The National Security Strategy Committee said there is no margin for complacency and that officials are not confident the country could prevent sabotage of its communications links or recover quickly if an attack occurred.

The committee’s review notes that about 50 subsea data-cable systems connect Britain to global networks. Globally, roughly 570 cables carry the vast majority of intercontinental telecommunications data, with about 80 more planned. These cables, many operated by private firms, form the backbone of daily life and critical services, from routine messages to trillions of dollars in financial transactions. The UK is almost entirely reliant on this network for data transmission, and security preparations for the network are described as inadequate. The committee said the UK’s military is 'too timid' defending pipelines and must adopt a 'muscular' approach.

The report highlights a security environment in which state actors could target infrastructure in a crisis. It notes Russian ships have surveyed undersea cables near the UK, and it cites attacks on cables at the bottom of the Baltic Sea in 2024. Finnish authorities also seized a Russian-linked shadow fleet tanker suspected of involvement in a plot to sever power cables in the Baltic. The findings come as Moscow has taken provocative steps near NATO borders, including actions that led to debates about resilience after Russia invaded NATO airspace over Poland and sent unmanned drones into the country.

The cables are the invisible backbone of the internet. They carry the data that power the economy, everyday communications and critical services. The committee warns that, while there is no immediate, visible threat, the trend toward high-capacity cables concentrates value on a small number of high-value routes. As one of the world’s island nations, the UK is almost entirely dependent on subsea cables to connect with the outside world and to onward-transit transatlantic traffic. The report emphasizes that the UK should not rely on luck; instead, it should prepare for the possibility that cables could be threatened in a security crisis and develop capabilities to prevent, detect, and recover from such disruptions. It calls for speedier repairs, more military exercises to practice protecting cables, legal changes to impose tougher penalties for malicious damage, and new integrated monitoring and alert systems to improve early warning and vessel interception. Subsea cables globally form a network through which around 95% to 99% of intercontinental telecommunications data flows, far surpassing satellites in capacity for cross-border data transfer.