All five Royal Navy Astute-class attack submarines are in port at once, leaving Britain without a hunter-killer at sea

Every one of the Royal Navy's five Astute-class attack submarines is currently alongside, with none at sea, the UK Defence Journal reports. Availability stayed badly depressed throughout 2025, a year in which the boats are reckoned to have managed only around 300 days at sea between them, and earlier in 2026 only one -- HMS Anson, the most active of the fleet -- was genuinely fully operational. Anson spent the early part of the year at HMAS Stirling in Australia, becoming the first British nuclear submarine ever maintained on Australian soil under the AUKUS arrangement meant to help Canberra build the workforce for its own future boats; her return home merely parks another hull rather than putting one back on patrol.

The boats are not ones the country can easily do without. The Astutes are the navy's hunter-killers, carrying Tomahawk land-attack cruise missiles and Spearfish heavyweight torpedoes, gathering intelligence, shielding the carrier strike group and, above all, screening the ballistic-missile submarines on which the nuclear deterrent rests. With the whole class in harbour, Britain loses the ability to slip that firepower or covert surveillance quietly to sea at short notice -- no academic worry given how much more active Russian submarines have become across European waters. The First Sea Lord warned in December that the advantage allied navies once took for granted beneath the Atlantic was now "at risk" and the margin over Russia "uncomfortably narrow."

The Ministry of Defence declined to comment on specifics, saying it does not routinely discuss individual submarine operations while insisting British waters are protected by warships, patrol aircraft and submarines. In Parliament, defence minister Lord Coaker would not say how many boats are operational at any one time, pointing instead to the recovery plan. The cause lies less in anything going wrong on patrol than in the cost and difficulty of maintenance: a chronic shortage of specialist dock space, with deep maintenance and refitting possible only at Devonport, the sole UK site equipped for the work, while the demand of keeping a deterrent submarine on patrol every day swallows much of the capacity -- problems the House of Commons Library has flagged for years alongside manpower and skills shortages.

The navy formally launched the Submarine Maintenance Recovery Plan on January 14 to pull scattered maintenance efforts under one structure. The First Sea Lord, General Sir Gwyn Jenkins, who said "submarine maintenance throughput needs to drastically improve," travelled to the Clyde on January 20 with the Chief of Defence Nuclear, Madeline McTernan; the most visible early change is a roughly 90-square-metre deployable workshop assembled from containerised facilities, including a covered workspace built from eight shipping containers under a contract worth just under 69,000 pounds with the Shropshire firm Beaverfit. The bigger fix is meant to come from Programme Euston, a plan to procure floating dry docks for which the National Shipbuilding Office has been consulted but no contract date set, while day-to-day support at Devonport has been propped up by a six-month stopgap deal with Babcock after the previous five-year contract expired at the end of March.

Further out, the 2025 Strategic Defence Review committed Britain to building as many as 12 next-generation attack submarines under the SSN-AUKUS programme with the United States and Australia, on top of the Dreadnought-class deterrent boats due from the early 2030s. The Astute class itself is still being completed -- the sixth boat, HMS Agamemnon, is commissioned but not yet fully worked up, and the seventh remains under construction. None of that helps the immediate problem of getting even two or three of the existing boats back to sea at the same time.