Government must take bolder steps to safeguard Britain's undersea cables
Undersea communication cables on the ocean floor (David Fleetham / Alamy)
5 min read
Conservative peer and former chair of the Joint Intelligence Committee Baroness Neville-Jones on how to secure our vital undersea cables
The UK is a global connectivity hub – the result of our industrial history and our Atlantic geography. The massive transatlantic undersea cables that land in the UK not only play a vital role in the daily functioning of the British economy but are linked to cables carrying data – on which the global internet and cloud computing depend – on to continental Europe, Africa and the Indo-Pacific region. This concentration of high-value assets – private sector as well as public – carries risk, which requires protection against accidental damage from shipping and exposes the UK to hostile state activity including espionage and sabotage.
Targeting undersea cables is as old as their existence. Today, the strength and resilience of UK undersea cables makes doing major damage, with extensive economic effects, difficult to execute. As we have seen, however, more limited damage is perfectly possible, and espionage – acquiring sensitive information about cables for later potential use – is easy to engage in and difficult to prevent. The defence task is therefore not just to ensure security for today but for the future too, which is why we cannot be relaxed about the interest that Russian vessels like the Yantar take in the UK’s coastline.
Russia now operates a shadow fleet designed to evade oil sanctions and uses it for other deniable purposes
The subsea domain is especially well-suited to Russian “sub threshold” activity, which blurs the distinction between war and peace and creates a ladder towards increasingly intrusive abuse of the norms of international behaviour. Russia now operates a shadow fleet designed to evade oil sanctions and uses it for other deniable purposes as well such as anchor dragging over cables in the Baltic Sea.
Worried about the developing situation, the parliamentary Joint Committee on the National Security Strategy (JCNSS) published a report in September 2025 entitled Subsea telecommunications cables: resilience and crisis preparedness. A business-as-usual approach was no longer adequate, it asserted. We would typically rely, in the event of attack, on the availability for rerouting via spare capacity in lots of cables. But that is not sufficient, according to the report, in the context of open hostilities increasing the UK’s strategic vulnerability to broader co-ordinated attacks
The government had a duty, it said, to provide against low-likelihood, high-impact events. The report also called for target hardening of cable landing stations and pointed to the vulnerability of concentrations of cables which would benefit from greater protection. There needed to be live exercises.
It also said the government should recreate sovereign repair capacity by replacing the repair ship recently sold to Singapore by 2030 and ensure the training of a reserve force of repair experts. It criticised risk assessment and contingency planning as inadequate and called for the Department for Science, Innovation and Technology (DSIT) to provide a “central co-ordinating brain” within government to ensure resilience of the system and to act as a contact point for industry and international partners.
DSIT ministers replied on 17 December 2025. They agreed that as the threat landscape evolved it was essential that risk assessments, contingency plans and legal frameworks governing undersea cables – some of which they were reviewing – remained robust and fit for purpose. They accepted some of the recommendations in full and the sense of several others, including broadening the range of risk scenarios to include sabotage and reducing, where possible, cable concentrations while considering the creation, again where possible, of cable protection zones.
Ministers said they were looking at options to obtain a repair ship and at ways in which a cadre of repair specialists could be created. On governance, they said DSIT should work with the Cabinet Office to ensure that all lead departments had sector analyses and response plans. And they agreed that, together with the Ministry of Defence, with which it would also work closely, DSIT should be the contact point for industry and international partners. Strategic direction of policy would be set by a senior level Undersea Infrastructure Security (UIS) oversight board chaired by the Cabinet Office.
Notwithstanding this largely positive response – the effectiveness of which depends on the promises made actually materialising – the reader is left feeling that the government and the committee are not entirely on the same page as regards the severity or urgency of the threat and, consequently, its management.
The committee has determined that more muscular deterrence of grey zone activity is the key, with interdiction and prosecution on the agenda. In its reply, the government largely sidesteps the issue of more assertive responses and rejects some of the committee’s ideas on the grounds that they could invite retaliation and endanger the authority of the United Nations Convention on the Law of the Sea, which it considers a bulwark of the UK’s policy.
Referring to the Strategic Defence Review, the government points to the future prospect of underwater sensors and drones offering easier and more effective protection of undersea assets as well as the “new class of ships optimised as a fleet of autonomy command platforms” which will be introduced “in coming years”. The timescale is unspecified.
Policy edges forward, but not radically or at pace. It is curious, in my view, that an island country with the UK’s geography on the edge of one of the great – and contested – oceans of the world messes about in this way rather than embedding, in support of the Royal Navy’s ocean going role, a uniformed Coast Guard dedicated to ensuring the resilience of the UK’s assets along our shoreline and in our close waters.
