The expansion forms part of an approximately £6 billion modernisation programme covering Raynesway, BAE Systems’ Barrow shipyard and specialist suppliers. Britain wants to double its submarine construction rate and establish continuous production of one SSN-AUKUS boat every 18 months.
Work at Raynesway includes construction of a Primary Components and Operations Facility, according to the government’s *Defence Nuclear Enterprise 2026 Annual Update to Parliament*. Rolls-Royce is also adding advanced prototyping infrastructure and improving site access to accommodate a larger specialist workforce.
The investment is designed to increase reactor-production capacity while Dreadnought construction continues at Barrow. The four Dreadnought-class ballistic-missile submarines will replace the Vanguard class and sustain Britain’s continuous at-sea nuclear deterrent.
HMS *Dreadnought*, the first boat in the class, is expected to complete sea trials and be ready to enter Royal Navy service in the early 2030s. The wider construction programme remains within its £41 billion cost envelope, although the government says it faces significant pressures and risks.
SSN-AUKUS will replace the Royal Navy’s Astute-class attack submarines and is scheduled to enter British service in the late 2030s. Steel cutting for the first UK boat is planned for 2027, while contracts worth about £4 billion have already been placed for design and industrial infrastructure.
Britain has yet to determine the number of SSN-AUKUS submarines it will purchase. A fleet-size decision is expected before the Detailed Design and Long Lead phase concludes in 2028.
Australia will build its submarines at the Osborne Naval Shipyard in South Australia, but their reactors will come from Raynesway. Britain will also supply key components while Australia expands its domestic submarine-manufacturing capacity.
Canberra is investing £2.4 billion over ten years to expand Rolls-Royce infrastructure and share the cost of designing SSN-AUKUS. The arrangement gives British industry a continuing role across the Royal Navy and Royal Australian Navy fleets.
The government is also investing in suppliers specialising in propulsion systems, electrical switchgear and precision engineering. Expanding those companies is intended to reduce production risks and ensure the wider industrial base can support two British submarine classes and Australia’s future fleet.
Rolls-Royce provides the nuclear propulsion plants used across every class of British submarine and supports them throughout their service lives. The Raynesway expansion is intended to turn that existing capability into a higher-volume production base for Britain’s deterrent, attack-submarine and AUKUS commitments.
