UK seeks US support deal worth up to 1bn for new AUKUS subs

The United Kingdom has requested US support, valued at up to USD 1 billion, for submarine combat systems, technical assistance and personnel as part of the AUKUS programme.

According to a US Foreign Military Sales notification, the package represents a major expansion of an earlier $50 million case and supports the development of next-generation nuclear-powered attack submarines for both the Royal Navy and Royal Australian Navy.

The new estimated value reflects the maximum estimated value of the proposed support, rather than a confirmed contract. The request includes a wide range of highly specialised systems and services tied to submarine combat architecture.

“The government of the United Kingdom (UK) has requested to buy technical assistance to the design and development of AUKUS-specific vertical deployment tubes; common weapon launchers… network input output units; servers and switches and custom electronics… simulation equipment… software and source code… and embedded U.S. and UK personnel… to support submarine design,” the notice states.

It also covers extensive engineering and programme support.

“Other support services included are U.S. government and contractor engineering, technical, and logistics support services; test and trials support; studies and surveys… and other related elements of logistics and program support,” it adds.

The revised value reflects the scale of integration required under AUKUS, moving beyond initial design support to a more comprehensive development and delivery effort.

The US said the package would directly strengthen UK capability.

“This proposed sale will support the foreign policy and national security objectives of the United States by improving the security of a NATO Ally that is an important force for political stability and economic progress in Europe.

The proposed sale will improve the UK’s capability to meet current and future threats by providing an effective combatant deterrent capability to protect maritime interests and infrastructure. This acquisition will enhance stability and maritime security in the northwestern region of Europe and contribute to the security and strategic objectives of NATO and the United States. The UK will have no difficulty absorbing this equipment into its armed forces.”

Despite the scale of the programme, the US assessed that the support would not shift regional dynamics. “The proposed sale of this equipment and support will not alter the basic military balance in the region,” the notice states, adding there would be no adverse impact on US readiness.

SSN-AUKUS

The SSN-AUKUS programme is a planned class of nuclear-powered attack submarines to be operated by the Royal Navy and the Royal Australian Navy, with entry into service expected from the late 2030s and early 2040s respectively. The design will replace the UK Astute-class. The programme emerged from the UK’s earlier Submersible Ship Nuclear Replacement effort, which was formally integrated into the AUKUS partnership in 2023, bringing in Australia and incorporating US technology.

The United Kingdom intends to build up to twelve submarines, while Australia plans to build five domestically alongside the interim acquisition of three US Virginia-class boats. The programme reflects a high degree of trilateral integration, with shared components, joint training, and coordinated maintenance arrangements between the UK, Australia, and the United States. This approach is intended to improve interoperability and streamline long-term support.

Technically, the submarines are expected to displace over 10,000 tonnes and will be powered by Rolls-Royce PWR3+ nuclear reactors driving pump-jet propulsion. The design draws heavily on US systems, including elements of the propulsion plant, combat systems, and weapons architecture, aligning it in part with the Virginia-class.