The Island-class is a class of Police patrol boat operated primarily by the MOD Police Clyde Marine Unit at HMNB Clyde. They are tasked with protecting high value Royal Navy ships such as the Vanguard-class submarines. Royal Marines currently operate two ex police boats of the class Mull and Rona- these were handed over to the Royal Marines during 2013. Rona and Mull are interchangeable in their roles and can be used by both RM and MDP. The RMs also have a third vessel named Eorsa. Mod Police Portsmouth Marine Unit also operate Gigha and Lewis. Gigha was the prototype and first of class.