PARIS — The United Kingdom’s Royal Navy has a “serious anti-submarine warfare gap” that weakens the country’s ability to respond to Russia’s submarine and underwater-sabotage threat, a parliamentary committee on defense in the High North found.

The Royal Navy currently has only five Type 23 frigates for anti-submarine warfare in service, compared with a stated requirement of eight, and analysis suggests the number of frigates equipped with a towed array sonar could remain as low as five for the next three years, the Defence Committee wrote in an inquiry report published on Thursday.

Anti-submarine warfare frigates are “critical” to helping locate Russian submarines, both in the High North as well as in British home waters, including to protect the U.K.’s ballistic missile submarines that provide the country’s nuclear deterrent when entering or leaving their base in Faslane, Scotland, according to the report.

“Although new frigates will eventually join the fleet in sufficient numbers, the current fleet readiness picture raises doubts about whether the U.K. could sustain the maritime tasks required in the High North by 2030,” the committee said.

Citing the critical role of anti-submarine operations in the High North, the committee recommended the government ensures no further Type 23 frigates equipped with towed sonar leave Navy service until they’re replaced on a one-on-one basis by the future Type 26 frigates.

The U.K. has ordered eight Type 26 frigates from BAE Systems for the anti-submarine warfare role, with the lead vessel scheduled to enter service in 2028, and Minister of State for Defence Luke Pollard said in June that the program remained on track. Norway said in August 2025 it would buy five Type 26s, with delivery to start in 2030.

Should two of the Type 26 frigates being built for the U.K. instead go to Norway to meet the delivery deadline, the Royal Navy would take until 2037 to meet its requirement for a fleet of eight frigates equipped with a towed array sonar.

“Export success must not come at the expense of the Royal Navy’s own Type 26 frigate delivery timelines,” the committee said. “The government must ensure that naval exports expand industrial capacity and allied capability, rather than competing with U.K. requirements for scarce ships, systems and skilled labor.”The High North, which the committee defined as the greater Arctic and parts of the North Atlantic, “has become central” in U.K. defense and security concerns, with climate change increasing access to the region, according to the report.

As melting ice sheets and sea ice expose Russian bases that were previously mostly inaccessible, Russia is seeking both to defend those bases as well as project force into the Atlantic and U.K. territorial waters, according to the committee. That threatens NATO supply lines from the United States to Europe, as well as undersea and onshore infrastructure, including the U.K.’s nuclear deterrent.

Lack of a credible under-ice capability means the Navy is less able to contest Russian freedom of action in the High North, which risks forcing the U.K. into a more defensive posture, according to the report. The Defence Committee asked the government to brief panel members on progress towards re-establishing an under-ice capability for at least some of the country’s Astute-class nuclear-powered attack submarines.

The Navy’s ASW frigates and nuclear-powered submarines offer the greatest deterrent against the threat posed by Russian submarines and underwater sabotage, though “unfortunately, they are either aging or too often unavailable due to maintenance issues,” the committee report said.

For the U.K. to lead an effective coalition would require the country to address “glaring gaps” in the availability of its maritime forces, and an agreed plan with European allies to deter and if necessary defeat any aggression in the High North from 2030, according to the report.

The committee asked the Ministry of Defence to provide a classified assessment of the capability gaps in case of a conflict in the High North in 2030 in which the U.K. and allies would operate without U.S. support.

“Royal Navy equipment readiness and platform numbers in particular are currently far worse than the government’s stated requirements,” the report said. “With 2030 identified as a key date by which to be ready to deter or defeat any Russian threat, dramatic progress is required before the end of the decade to improve the availability and capabilities of the U.K.’s Armed Forces for operations in the High North.”The Royal Navy has a requirement for 13 frigates and six destroyers, but has struggled to meet those numbers, the committee said, with only the five Type 23 frigates and six Type 45 destroyers in service.

With the Northern Sea Route becoming more accessible, Russia may try to turn control there into a monopoly, and the government should prepare options for a U.K. state-owned vessel to transit the route to support freedom of navigation, the committee said. Sailing from Shanghai to Rotterdam takes about 14,900 kilometers via the northern route, compared with 19,500 km via the Suez Canal.

The report raised questions about the U.K.’s Hybrid Navy program to combine crewed and uncrewed vessels, saying the High North is “an exceptionally demanding environment” for autonomous systems, and the concept should not become a substitute for crewed capability before unmanned systems have been proven in harsh Arctic conditions.

The committee recommended the government explain within a year how it will test the Hybrid Navy’s main uncrewed systems in High North conditions before relying on them for operational tasks, looking at issues such as cold-weather performance, resistance to jamming and protection from capture.