The programme is designed to allow Britain to construct SSN-AUKUS attack submarines alongside Dreadnought-class ballistic-missile submarines. The government outlined the plan in its Defence Nuclear Enterprise 2026 Annual Update to Parliament.
Investment will focus on BAE Systems’ submarine shipyard at Barrow-in-Furness, Rolls-Royce Submarines’ Raynesway reactor facility near Derby and companies supplying specialised equipment. The expansion is intended to create the industrial capacity required for a larger attack-submarine fleet while sustaining delivery of the nuclear deterrent.
Work at Raynesway is already under way, including construction of the Primary Components and Operations Facility. Improved site access and advanced prototyping facilities are also being introduced to support a larger engineering and manufacturing workforce.
At Barrow, the concept design for SMITE2, a new submarine propulsion testing facility, was completed in early 2026. The facility will provide expanded engine and machinery assessment capacity needed to support the accelerated production schedule.
Preparatory work at Ramsden Dock has also progressed ahead of future manufacturing infrastructure projects. The wider modernisation includes investment in digital design systems, advanced production technologies and training centres.
The government is directing additional investment towards suppliers specialising in propulsion systems, electrical switchgear and precision engineering. Expanding these companies is intended to strengthen the submarine supply chain and help it meet higher demand and strict quality requirements.
Steel cutting for the first British SSN-AUKUS submarine is planned for 2027, with entry into Royal Navy service targeted for the late 2030s. Decisions on the total number of boats to be ordered are expected before the programme’s Detailed Design and Long Lead phase ends in 2028.
Contracts worth about £4 billion have already been placed for submarine design and the infrastructure needed to support production. Britain is also establishing a Submarine Production Alliance involving the Ministry of Defence, BAE Systems, Rolls-Royce Submarines and Babcock to coordinate future programmes.
