The design review for the UK’s next-generation SSN-AUKUS submarine has finished three months earlier than expected.
The Preliminary Design Review was carried out in June 2026 and concluded on 1 July, Defence Minister Luke Pollard confirmed. It had been expected to reach that point in September.
What happens next?
The review fixes the submarine’s overall configuration before detailed design progresses at scale. That includes its hull, internal layout, propulsion and combat-system integration, as well as weight and stability limits.
Completing the stage allows long-lead components to be ordered against a more settled design. The Detailed Design and Long Lead phase is due to continue until 2028 and is now about halfway through.
SSN-AUKUS is being developed by BAE Systems at Barrow-in-Furness, with Rolls-Royce in Derby providing the reactor plant. It will replace the Astute class and is also being designed for construction in Australia, under the trilateral AUKUS arrangement.
The first British hull is due to begin construction next year. The new class will be larger than Astute, with vertical launch capacity and room for uncrewed systems alongside torpedoes and cruise missiles.
Why it matters for Britain
The programme is supporting specialist submarine design and reactor work at Barrow and Derby. Its progress also gives British industry a clearer path towards supplying a shared submarine design for both the UK and Australia.
