AUKUS

AUKUS is the trilateral security partnership announced in September 2021 by Australia, the United Kingdom, and the United States. It is structured around two pillars: Pillar I covers the transfer of nuclear-powered submarine technology to Australia under the SSN-AUKUS programme; Pillar II covers a broader advanced-capabilities agenda including artificial intelligence, quantum technologies, hypersonic weapons, electronic warfare, cyber, and undersea autonomy. The three nations operate AUKUS through senior defence ministerial and official meetings, with project-by-project decisions made at Pillar II level.

On 30 May 2026, AUKUS announced its first Pillar II Signature Project, a trilateral programme to develop payloads and enabling systems for uncrewed underwater vehicles (UUVs), with hardware deliveries beginning in 2027. The named platforms are both US-built: the Mission Specialist Defender Mk IV ROV and the L3Harris Iver4 900 AUV. No UK-built platform appeared in the published fact sheet. The project scope covers mine countermeasures, anti-submarine warfare, seabed-infrastructure protection, and contested-littoral manoeuvre.

The announcement came against a backdrop of accelerating UK autonomous-maritime deployments, including the crewless minehunter RNMB Ariadne's movement toward the Strait of Hormuz the previous week, and prior US industrial positioning in Britain's subsea-autonomy programmes through the HII-Babcock ARMOR Force initiative. The Pillar II Signature Project label elevates UUV collaboration above routine bilateral procurement and requires trilateral consensus on each delivery milestone.