Undersea Cables: National Security Threat

Viscount Stansgate Excerpts

Monday 27th October 2025 Lords Chamber

Asked by

[Viscount Stansgate]

To ask His Majesty’s Government what assessment they have made of the national security threat to undersea cables connected to the UK.

[Viscount Stansgate (Lab)]

In begging leave to ask the Question standing in my name on the Order Paper, I declare an interest: I was a member of the Joint Committee on the National Security Strategy earlier this year when we agreed to hold an inquiry into this subject.

[The Minister of State, Ministry of Defence (Lord Coaker) (Lab)]

My Lords, the Government keep the threat to undersea cables connected to the UK under close review, working to deter and mitigate identified risks. My noble friend will appreciate the limits to what can be said publicly, but the MoD constantly monitors activity within UK waters. This includes patrols conducted by Royal Navy assets, maritime patrol aircraft and the multi-role ocean surveillance programme. Following the strategic defence review, the Royal Navy will play a new leading and co-ordinating role, alongside the private sector, in securing undersea pipelines, cables and maritime traffic.

[Viscount Stansgate (Lab)]

I thank my noble friend for that Answer. The House knows better than it did that undersea cables—not to mention the land cables under the City of London—are part of our critical national infrastructure because of the vital importance of the data they carry. The Joint Committee’s report said that “security vulnerabilities abound”. It recommended that we develop a UK-flagged sovereign repair ship, which the Royal Navy should practise escorting. Should we develop a seabed warfare strategy and, if so, what are the Government doing about it?

[Lord Coaker (Lab)]

We certainly should develop one, and we are developing one. My noble friend is right to highlight that. We are undertaking a number of actions including surveillance aircraft from Lossiemouth, the ship “Proteus” looking at how it protects underwater assets, and the Royal Navy ship “Stirling Castle” looking at how it might operate drones from its deck to secure underwater pipelines, data cables and so on. We are doing a lot, but my noble friend is right to point out the importance of this.