French navy surveillance crew patrols the Baltic Sea to protect undersea cables and pipelines. Photo Credit: https://www.theguardian.com/politics/2025/jun/15/uk-woefully-ill-protected-against-chinese-and-russian-undersea-cable-sabotage
New Think‑Tank Warns China and Russia May Target Undersea Cables; UK Radar Covers Only 22% of Its EEZ
A recent analysis from the China Strategic Risks Institute (CSRI) reveals a growing threat to undersea internet cables, warning that China and Russia are employing “grey‑zone” tactics—using shadow fleets to covertly target global communications infrastructure. Between January 2021 and April 2025, CSRI identified 12 suspicious incidents; in eight of the ten cases where a vessel was identified, links to Chinese or Russian ownership or flag registration were found.
Submarine cables carry over 99 percent of intercontinental internet traffic, underpinning global banking, cloud services, defence, logistics, and social connectivity. The UK, a major node with more than 60 cable landings—including nine of the 15 transatlantic cables—finds itself particularly exposed. However, current government data reveals that only 22 percent of the UK’s Exclusive Economic Zone (EEZ) is under coastal radar surveillance, posing serious monitoring gaps.
The UK Government has officially acknowledged these coverage limitations in testimony to Parliament, noting that high volumes of seemingly normal shipping traffic make it extremely challenging to identify and intercept suspect operations near critical cable infrastructure. CSRI’s Executive Director, Andrew Yeh, has called on the UK to bolster its maritime surveillance capabilities and to collaborate with partners experienced in grey‑zone defence, such as Taiwan.
In response, NATO has launched “Baltic Sentry,” a multi-domain operation in the Baltic Sea aimed at deterring further sabotage. The mission integrates frigates, maritime patrol aircraft, naval drones, and unmanned sensors to protect undersea cables and pipelines following a spate of disruptions in recent months. NATO’s new Maritime Centre for Security of Critical Undersea Infrastructure in London supports mapping, coordination, and surveillance integration. Domestically, the UK is investing in new surveillance platforms. The Royal Fleet Auxiliary’s RFA Proteus entered service in October 2023 to protect seabed infrastructure using remote and autonomous underwater systems. Defence Science and Technology Laboratory (DSTL) is also trialing Bond‑style underwater drones equipped with advanced sonar, cameras, and even payloads to detect and neutralise underwater threats. The Ministry of Defence has accelerated deployment of these capabilities following the Strategic Defence Review, and a second surveillance vessel is reportedly in development.
Yet analysts warn that legal and technological hurdles remain. The 1884 Cable Convention governing undersea infrastructure is widely considered outdated, offering weak powers to hold offending states accountable. Additionally, environmental factors—such as extreme sea conditions—can hinder deployment of inspection drones and surveillance assets, complicating timely threat response, as demonstrated during NATO’s “Freezing Winds” exercise last November.
Security experts advocate for a comprehensive approach: upgrading surface and undersea surveillance with acoustic seabed sensors, satellite-AIS data fusion, automated and crewless systems, and robust international legal frameworks. They point to advances in seabed-to-space situational awareness that combine AUVs, satellite imagery, and AI-driven sensor fusion.
In summary, this emerging security dimension highlights that maritime defence must now include digital infrastructure protection. With undersea cables representing strategic national assets, countries must reassess maritime doctrine, invest in dual-domain surveillance systems, modernise laws, and pursue multinational collaboration to deter sabotage. The UK’s limited EEZ coverage signals that much remains to be done.
