UKDI: Three naval testbeds transform defence innovation
Source: gov.uk (2025-09-30)

Royal Navy's ASW Spearhead programme rapidly developed three autonomous testbed platforms – CETUS, PROTEUS, and SCYLLA – to enhance ASW capabilities.

- CETUS: One of the largest autonomous underwater vehicles (20 tonnes, 12 metres) began trials with the Royal Navy in February 2025
- PROTEUS: 3-tonne autonomous rotary platform is demonstrating rapid concept-to-hardware development for dangerous missions and future maritime surveillance
- SCYLLA: Submarine-launched autonomous system is conducting ASTUTE-class integration trials, supporting AUKUS seabed warfare objectives
A collaboration between the Royal Navy, defence industry, and research organisations has rapidly delivered three autonomous platforms that will strengthen Britain’s naval capabilities and support AUKUS partnerships.

The Anti-Submarine Warfare (ASW) Spearhead programme demonstrates how innovative governance and joint working can accelerate defence technology from concept to capability. In just seven years, this £400 million initiative has produced three unique testbeds now enhancing our underwater and aerial operations.

Streamlined innovation process

The programme’s success stems from a 7-step governance framework that prioritised speed without compromising safety. This approach, championed by UK Defence Innovation (UKDI), enabled rapid development while maintaining rigorous operational standards.

Multi-year funding provided industry partners with the confidence to innovate and covered all development activities, ensuring that demonstrators could progress without traditional handover delays. The Defence Science Technology Laboratory (Dstl) provided technical support throughout the programme, acting as a cost cutting enabler and participating in panels to assess capability proposals.

CETUS: Britain’s largest autonomous submarine

Developed through a partnership between the Royal Navy and Plymouth-based MSubs Ltd, Cetus represents a shift in naval autonomous operations. Originally funded through a Dstl and Defence and Security Accelerator (DASA) project, MSubs delivered the £15.4 million, 12-metre autonomous underwater vehicle in November 2022 through the Submarine Delivery Agency (SDA). At 25 tonnes with full payload, Cetus is one of the most complex uncrewed submersibles used by any navy to date.

Lt Cdr David Iwanek, Underwater Battlespace Capability Sponsor said:

CETUS is our first venture into large-scale, under the sea uncrewed submarines. It’s exciting, the possibilities are enormous, and I like to think CETUS could change the way we fight.

The platform’s substantial payload bay enables diverse mission configurations including anti-submarine warfare, seabed operations, and intelligence gathering capabilities. CETUS will help the Royal Navy develop operational concepts for autonomous systems while addressing critical objectives including autonomous decision-making, advanced sensor miniaturisation, launch-recovery procedures, and system security protocols. The platform began sea trials in February 2025 and CETUS XLUUV was formally named XV EXCALIBUR in May 2025.

PROTEUS: Revolutionary autonomous aviation

The PROTEUS demonstrator showcases the programme’s agile approach, accelerating from initial requirements to hardware delivery within three years through innovative acquisition approaches. This 3-tonne autonomous rotary platform, delivered by Leonardo, serves as a testbed for autonomy and mission modularity, initially focusing on sonobuoy deployment and communications relay missions that are both critical to anti-submarine warfare operations.

PROTEUS addresses critical dangerous missions while reducing reliance on expensive crewed helicopter operations, delivering significant cost savings and risk reduction. Future capabilities will expand beyond sonobuoy operations to include logistics support, search and rescue coordination, and maritime surveillance missions.

SCYLLA: Torpedo tube launch and recovery system

Project SCYLLA is an autonomous torpedo tube launch and recovery system developed through Spearhead. The vehicle is designed to be launched then autonomously conduct missions and recover itself back into a submarine torpedo tube, enhancing submarine capabilities without requiring platform modifications.

SCYLLA features a modular mid-section, which allows mission-specific payload configurations for diverse operational requirements. Trials on ASTUTE-class submarines began in 2024-25, with Initial Operating Capability planned for 2026-27. The platform supports AUKUS Pillar 2 objectives by providing submarines with deployable autonomous vehicles capable of seabed warfare, intelligence operations, and covert surveillance missions.

Commander Chris Hill MBE RN, ASW Spearhead Programme Director said:

SCYLLA delivers a paradigm shift in ASW capabilities, the most significant since the introduction of Tomahawk. Working with AUKUS partners development is underway on a range of Seabed Warfare and ISR payloads for this expeditionary capability.

Securing Britain’s future

These three platforms demonstrate how collaborative innovation accelerates capability development whilst reducing costs and risks. The ASW Spearhead programme positions the Royal Navy at the forefront of autonomous naval warfare innovation, while reducing operational risks, lifecycle costs, and supporting broader AUKUS partnership objectives. This success validates UKDI’s innovative approach, proving that streamlined governance and strategic partnerships can rapidly transform defence capabilities.