Royal Navy Unveils Subsurface Drone Capable of Firing Torpedoes

The Royal Navy has successfully conducted its first torpedo launch from a deep-sea drone, a significant technological achievement for its unmanned naval capabilities. The 40-foot Excalibur vessel, which is crewless, fired a US-made torpedo during secret trials, mirroring the offensive capabilities of larger, manned submarines.

This development comes as the Royal Navy's fleet of manned hunter-killer submarines faces operational challenges. Recent reports indicate instances where not a single Astute-class submarine was available for active service due to maintenance issues and crew rotations, leading to extended patrols for the operational vessels. Some submarines have reportedly spent over 200 days at sea to compensate for these limitations.

The Excalibur, which is battery-operated and UK-built, has been undergoing trials since 2025. Although still experimental, it offers the potential to support the Navy's aging fleet. The drone can reportedly dive deeper than manned submarines and travel from the UK into the North Atlantic on a single battery charge. Naval insiders suggest that the addition of Excalibur-type vessels could not come soon enough.

Excalibur entered its trials phase in May 2025, with a ceremony held at His Majesty's Naval Base (HMNB) Devonport. The Royal Navy's current fleet of manned submarines has been increasingly stretched by a rise in Russian submarine activity in the North Atlantic.

A Downing Street spokesperson described the successful trial as "a major advance in the future of submarine technology." The breakthrough is expected to be a topic of discussion between UK Prime Minister Andy Burnham and US President Donald Trump during their upcoming talks in New York.

The development of Excalibur-type submarines is seen as a significant boost for UK security, particularly in safeguarding strategically vital undersea communication and energy cables. These cables have been subjected to surveillance by Russian vessels and could be vulnerable in a conflict. Excalibur could play a role in monitoring these critical infrastructures.

The torpedoes used in the trials are designed as part of the AUKUS submarine program, involving the UK, the US, and Australia, and are capable of targeting both surface and subsurface enemy vessels.

Excalibur was designed by the Plymouth-based maritime engineering company MSubs as part of a £6 million development contract. Initially conceived to carry additional equipment, thereby freeing up space on manned submarines, its capabilities have now expanded.

The vessel belongs to the Royal Navy's Fleet Experimentation Squadron. Over the next two years, further sea trials will aim to accelerate the integration of advanced technologies into the fleet. These trials will help the Royal Navy understand the challenges of operating large uncrewed vessels and pave the way for future collaborations between crewed and uncrewed platforms. The ongoing testing is crucial for maintaining the Royal Navy's technological edge, protecting key infrastructure, and gathering intelligence beneath the waves.