HMNB Clyde (Faslane)

His Majesty's Naval Base Clyde is the Royal Navy's principal shore establishment in Scotland and the home port of the United Kingdom's nuclear-powered submarine fleet. The main site lies on the eastern shore of Gare Loch, a sea loch running north from the Firth of Clyde in Argyll and Bute, about 25 miles (40 km) west of Glasgow. The base was selected for its access through the North Channel to North Atlantic patrol areas and the GIUK gap into the Norwegian Sea, reached from deep and readily navigable water.

The base berths the Vanguard-class ballistic missile submarines carrying the Trident deterrent, together with nuclear-powered attack submarines. The shore establishment is HMS Neptune; naval personnel appointed to the base who are not assigned to a seagoing unit form the ship's company. Command rests with the Naval Base Commander (Clyde), a commodore. Lodger units include 43 Commando Fleet Protection Group Royal Marines, responsible for security of the site and of the deterrent, Flag Officer Scotland and Northern Ireland — who also holds the appointment of Rear Admiral Submarines — the Northern Diving Group, and the Scottish headquarters of the Ministry of Defence Police. Some 3,000 service personnel and 4,000 civilian staff work at the base.

HMNB Clyde comprises several separate sites. Besides Faslane, the base includes the Royal Naval Armaments Depot at Coulport on Loch Long, roughly 2 miles (3.2 km) west of Faslane overland and about 19 miles (31 km) by sea, where Trident missiles are stored, maintained and issued. Faslane is also a Defence Equipment and Support site, run in a dual-site organisation with Great Harbour, Greenock, by Babcock Marine and Technology and managed by Serco Denholm. The Faslane site covers 87 hectares.

Faslane Port was built during the Second World War. Following the Polaris Sales Agreement of the 1960s, four purpose-built ballistic missile submarines — Resolution, Repulse, Renown and Revenge — were permanently based there. By 1971 the base hosted the 3rd Submarine Squadron of nuclear fleet and diesel patrol boats alongside the 10th Submarine Squadron of Polaris boats.