U.K. Royal Navy Commissions Former Support Vessel as Mine Hunting Warship

The U.K. Royal Navy has officially commissioned HMS Stirling Castle as a front-line warship, marking a shift in how the United Kingdom tackles underwater threats in its coastal waters.

Previously operated as RFA Stirling Castle under the Royal Fleet Auxiliary, the vessel was formally redesignated as a warship during a ceremony held today at the Cammell Laird facility in Birkenhead. The White Ensign was hoisted for the first time, and her 45-strong ship’s company moved onboard.

HMS Stirling Castle will act as a mother ship for autonomous and remotely operated systems, which will scan for mines and other threats beneath the surface. She will primarily operate in U.K. waters and support the Royal Navy’s Mine & Threat Exploitation Group, with potential to support allied missions in the future.

Originally launched as the offshore support vessel MV Island Crown, the ship was acquired by the U.K. Ministry of Defence in 2023 and refitted at HM Naval Base Devonport. Over the past 18 months, she served under the RFA to help test and integrate new mine countermeasure technologies.

Now commissioned, HMS Stirling Castle will be based at His Majesty’s Naval Base Portsmouth and dedicated full-time to maritime security operations. A change in her hull colour from blue and white to naval grey is expected as she transitions fully into the Royal Navy fleet.