UK’s Royal Navy has ‘serious’ anti-submarine warfare gap, committee finds

Anti-submarine warfare, or ASW, is the organized search for and response to hostile submarines. It involves detecting underwater contacts, tracking their movement, and deterring or defeating them when necessary. It matters because submarines can threaten naval forces, supply routes, infrastructure, and nuclear deterrent patrols.

The Royal Navy uses ASW frigates fitted with towed-array sonar and nuclear-powered submarines. These platforms help locate Russian submarines in the High North and British home waters. They also help protect the United Kingdom’s ballistic-missile submarines as they enter or leave Faslane in Scotland.

The committee found only five Type 23 ASW frigates in service, against a requirement for eight. It also warned that frigates with towed sonar could remain at five for three years. Aging ships and maintenance problems reduce availability, leaving the United Kingdom less able to contest Russian activity in the High North.

The Royal Navy’s current anti-submarine frigate gap is three ships. The Defence Committee reported five Type 23 frigates for ASW in service, compared with a stated requirement of eight. These ships are important for detecting Russian submarines and protecting key waters.

The shortfall is not only about the total number of hulls. The committee said the number equipped with towed-array sonar could remain as low as five for the next three years. That limits the fleet’s ability to maintain continuous submarine-hunting coverage in the High North and around the United Kingdom.

Eight future Type 26 frigates are intended for the ASW role, with the lead ship scheduled for service in 2028. However, the committee warned that possible exports to Norway could delay the Royal Navy’s eight-ship towed-sonar requirement until 2037. It urged one-for-one replacement of retiring Type 23 frigates.

A towed-array sonar is a long underwater sensor pulled behind a ship. It listens for sound in the ocean and helps operators detect and track submarines. The article identifies these systems as especially important for the Royal Navy’s anti-submarine frigates.

Towing the sensor places it away from much of the ship’s machinery and movement. That can make faint submarine sounds easier to distinguish from the ship’s own noise. The sonar helps frigates search for Russian submarines in the High North, the North Atlantic, and British home waters.

The Royal Navy currently has five Type 23 ASW frigates, while its requirement is eight. The committee warned that the number of frigates with towed-array sonar could stay as low as five for three years. Future Type 26 frigates are meant to replace these ships, but delivery timing remains central to the capability gap.

If Russian submarines operate more freely, they could threaten the sea routes connecting the United States and Europe. The Defence Committee also identified risks to undersea and onshore infrastructure, including systems supporting the United Kingdom’s nuclear deterrent.

The key mechanism is persistent underwater access. Russian submarines could project force from bases in the High North into the Atlantic and U.K. territorial waters. Underwater sabotage could further endanger infrastructure. If the Royal Navy cannot reliably detect and track those movements, it would have fewer options to protect supply lines or challenge Russian activity.

The committee said the lack of a credible under-ice capability could force the U.K. into a more defensive posture. It called for progress toward restoring under-ice operations for some Astute-class attack submarines. It also requested a classified assessment of gaps in a 2030 conflict without U.S. support.

The High North has become more important because climate change is increasing access to the greater Arctic and parts of the North Atlantic. Melting ice sheets and sea ice are making areas that were previously mostly inaccessible easier to reach. That changes the military and security environment.

The article says Russia is responding in two ways. It is defending bases that are becoming more exposed, while also seeking to project force into the Atlantic and U.K. territorial waters. The Northern Sea Route is becoming more accessible too, raising concerns that Russia may seek control of it as a monopoly.

This matters because the region connects Russian military activity with NATO supply lines and undersea infrastructure. The committee wants the U.K. to improve maritime readiness, restore at least some under-ice capability, and work with European allies on a plan to deter or defeat aggression by 2030.

The United Kingdom could strengthen submarine monitoring through several layers of capability. The article directly identifies nuclear-powered attack submarines and ASW frigates as major deterrents. Allied European forces could add ships, submarines, sensors, and shared planning. Uncrewed vessels are a possible additional tool, but the article does not describe a U.K. program using them.

Nuclear-powered submarines can operate for long periods and, if equipped and trained for it, support under-ice surveillance. The committee specifically requested progress toward re-establishing under-ice capability for some Astute-class submarines. Allied forces could spread patrol responsibilities and improve coverage across the High North and North Atlantic.

The current problem is availability. Ships and submarines are aging or often unavailable because of maintenance. The U.K. also has only five ASW Type 23 frigates against eight required. By 2030, stronger national readiness and a European plan would be needed for credible deterrence.

Sonar gives ships and submarines a way to detect underwater contacts, while stealth helps a submarine avoid detection. Anti-submarine warfare tries to overcome that stealth by using sensors, quiet operations, tracking, and coordinated patrols. The balance matters most around the United Kingdom’s nuclear deterrent.

The article says ASW frigates are critical for locating Russian submarines in British waters. They also help protect ballistic-missile submarines entering or leaving Faslane in Scotland. Nuclear-powered attack submarines provide another layer of deterrence and could support under-ice operations if that capability is restored.

The protection system is weakened when sonar-equipped frigates are unavailable or when submarines lack under-ice capability. The Navy has five ASW Type 23 frigates against eight required, while ships and submarines face aging and maintenance problems. The committee wants replacements, better readiness, and progress toward under-ice operations before 2030.