British Royal Navy attack submarines are tasked with monitoring Russian submarine movements in the North Atlantic and serve as one of the first lines of Russian deterrence that profoundly benefits the United States. Such monitoring is especially critical to U.S. national security because Russia boasts a robust submarine force that has exercised heightened submarine activity in the region and beyond. Russian submarines have been identified in the past year near Portugal, the Irish Sea, the North Sea, the Mediterranean, the Caribbean, and the United States.

However, the waves of crisis are cresting for a naval force once unequivocally considered the most powerful in the world. For nearly 100 days this year, none of the British Royal Navy’s attack submarines were deployed to conduct naval operations. Altogether, only nine of 25 total warships and attack submarines remain active, collectively racking up an appalling 30 years’ worth of missed days at sea.

And the issues potentially just got much worse. On early Wednesday morning, a significant fire broke out at the northwestern England shipyard that builds the Royal Navy’s nuclear submarines. It’s still unclear what the extent of the damage is, and British authorities are still investigating the cause.

The British naval force is comprised of four Vanguard-class ballistic missile submarines, which are tasked with nuclear deterrence, and six attack submarines of the Trafalgar class and Astute class, which carry conventional missiles. The Astute class subs remained out of water, dry-docked on what’s known as a shiplift for maintenance for over three months this year, from July 3 to Oct. 7.

When British nuclear-powered attack submarines are not rusting pier-side or on a shiplift, their few numbers are being exhausted—not unlike their American counterparts. Submarines are serving increasingly long missions, stressing aging hulls and hardware, and burning out crews.

Over the last three years, the average amount of time attack subs spend at sea has nearly doubled. Missions have stretched up to 207 days long, with comparable United States patrols lasting around 77 days.

Infrastructural woes threaten an increasingly limited force. The Royal Navy’s submarine force lacks a sufficient number of functioning docks for underwater maintenance work, creating unacceptable delays in accommodating new Astute-class vessels.

Recently, the Royal Navy has also struggled to meet increasingly strict safety standards. The shiplift at the Faslane naval base in Scotland unexpectedly failed certification inspection and remained nonoperational for over a year, creating backlogs and disturbing regularly ordered maintenance schedules for the submarine fleet.

The British Royal Navy faces another critical issue—maintaining personnel. The force must contend with a critical shortage of marine engineers, particularly engineers with experience. Though the navy has enacted benefits programs, retention is a significant problem as technical staff salaries are not competitive with the commercial world.

The Royal Navy must also navigate the arduous task of finding and keeping submariners (crewmembers), having exacerbated an already difficult recruitment and retention process with marathon patrols and inconsistent deployments back to sea.

This crisis extends beyond attack submarines. Over the past 23 years, Royal Navy personnel numbers have fallen by 24%. British ships are operating at a significantly reduced capacity. The destroyer force currently operates at only 50% capacity, and nearly 40% of frigates are not currently operational. The British Royal Navy is in critical condition.

The United States faces mounting national security threats around the world, from Beijing to Moscow to Tehran. As a close United States ally in an increasingly volatile environment for defense interests, Britain must take control of its own national security.

While the United States shifts resources and attention to the Indo-Pacific to counter China’s increasingly belligerent military posturing there, close allies must fulfill their regional security commitments. If the British can’t or won’t, it may fall to French and German submarines to patrol the North Atlantic.

If the United Kingdom is to lead NATO’s deterrence of Russia in the North Atlantic and beyond while supporting wider United States geostrategic interests against an expansionist China, it must start taking its navy more seriously.