Construction of the first SSN-AUKUS attack submarine will begin next year, with the Defence Investment Plan confirming the commitment to build up to 12 of the next-generation boats for the Royal Navy.
The plan states the UK is "building up to 12 next-generation SSN-A nuclear powered, conventionally armed attack submarines, and we will cut steel on the first boat next year," adding that "these will be the same class of submarines that Australia will also build under AUKUS." Alongside the boats themselves, the document lists investment in weapons systems and sensors for underwater drones as the signature project under AUKUS Pillar 2, the strand of the partnership covering advanced technologies rather than the submarines.
SSN-AUKUS is the successor to the Astute class, a design based on the UK's next-generation attack submarine adapted to incorporate American and Australian technology under the trilateral partnership. The British boats will be built by BAE Systems at Barrow-in-Furness with their reactors manufactured by Rolls-Royce at Raynesway in Derby, the same sites building the Dreadnought ballistic missile submarines, and Australia plans to construct boats of the same class at Osborne in South Australia, having also arranged to buy three American Virginia-class submarines to bridge the gap until its own production line is running. Defence minister Lord Coaker revealed this week that the fifth SSN-AUKUS reactor is already in manufacture at Raynesway, where Rolls-Royce has broken ground on a doubling of the site.
The plan supports the build with a series of industrial commitments across the Defence Nuclear Enterprise, including a Submarine Build Modernisation effort to expand manufacturing capacity, accelerate production and improve productivity in support of AUKUS, the expansion of reactor core manufacturing at Raynesway for the UK and Australian navies, a multi-decade infrastructure programme at HM Naval Base Clyde to ready the base for Dreadnought and SSN-A boats, three floating docks at Faslane enabling out-of-water engineering for all submarine classes, and dock upgrades at Devonport. A Nuclear Fuels Programme backed by £1.7 billion will explore re-establishing a nuclear fuel cycle for defence reactor fuel, and the Defence Nuclear Enterprise will invest over £290 million in nuclear skills.
The steel cut will come with Barrow already at an unprecedented tempo, with the final Astute completing, the four Dreadnought boats in build following the start of construction on HMS King George VI last year, and the first SSN-A joining them on the ways. Overall nuclear deterrent spending in the plan runs to £63 billion over the next four years across Dreadnought, SSN-AUKUS and the warhead programme, and the government is targeting a drumbeat of a new submarine every 18 months from the expanded Barrow and Raynesway facilities, a rate some analysis has described as demanding without further capacity growth.
