The Vanguard-class is a class of ballistic missile submarine operated by the Royal Navy with the designation Ship Submersible Ballistic Nuclear (SSBN). There are currently four Vanguard-class submarines in service and together they provide the United Kingdoms's nuclear deterrent.
In March 1982 the British Government announced that it would purchase a quantity of U.S. Trident ballistic missiles to be deployed in four purpose-built submarines. The first of these, HMS Vanguard, was ordered in 1986 and entered commission in August 1993. HMS Victorious was the next to be commissioned, in 1995, followed by HMS Vigilant in 1996 and HMS Vengeance in 1999. All four were built by Vickers Shipbuilding and Engineering in Barrow-in-Furness.
- Displacement: 15,980 tons
- Length: 149.9m
- Beam: 12.8m
- Draught: 12m
- Speed (dived): 25 knots
- Crew: 135
- Armament: 16 Trident capable missile tubes, 4 torpedo tubes
As a result of the 1998 Strategic Defence Review the four Vanguard-class submarines now represent the United Kingdom's main nuclear deterrent. Each submarine can carry 16 Trident missiles, with each missile containing up to 12 warheads (MIRV or multiple independently targetable reentry vehicles).