Her Majesty's Naval Base, Devonport (HMNB Devonport), is one of three operating bases in the United Kingdom for the Royal Navy. HMNB Devonport is located in Devonport, in the west of the city of Plymouth, England. Having begun as Royal Navy Dockyard in the late-17th century, it is now the largest naval base in Western Europe and is the sole nuclear repair and refuelling facility for the Royal Navy.