UK SDR 2025: Review calls for Royal Navy to take on leading role in CUI protection

RFA Proteus (background), the UK's first underwater surveillance ship, monitors Russian spy ship Yantar as it passes through UK waters in November 2024. (UK MoD/Crown Copyright)

The UK Strategic Defence Review (SDR) 2025 has called on the Royal Navy (RN) to play a new leading role in protecting the UK's critical undersea infrastructure (CUI) and key shipping routes.

Published on 2 June, the SDR said that maritime security remains a “strategic imperative” for the UK, with global trade, undersea pipelines and data cables, and offshore energy installations being critical for sustaining daily national life.

However, with the maritime domain becoming increasingly vulnerable, the review suggested that the RN should be more prepared to deter maritime incidents similar to the sabotage of the Nord Stream 2 gas pipeline and the cutting of undersea data cables in the UK and national waters. “The UK is already subject to daily sub-threshold attack, targeting its critical national infrastructure, testing its vulnerabilities as an open economy and global trading nation, and challenging its social cohesion,” it said.

The SDR said that much greater focus is needed on ensuring the UK's critical national infrastructure is protected from attack below and above the threshold of war, and that close co-ordination with the rest of government, industry, and allies will be needed to achieve such. It added that this could potentially be under a new model for government/industry collaboration.

As part of this effort, the SDR has recommended that the RN improve its detection capacity and ability to co-ordinate tasks via enhanced command-and-control through the development of a global decision support system – focusing on the Euro-Atlantic in the first instance; use its the Multi-Role Ocean Survey ship RFA Proteus