The independent resource on global security

The United Kingdom

The United Kingdom’s nuclear deterrent consists exclusively of a sea-based component: Vanguard class Trident nuclear-powered ballistic missile submarines (SSBNs) armed with the UGM-133 Trident II D5 submarine- launched ballistic missile (SLBM) and associated warheads, and their support infrastructure.

The UK possesses an arsenal of about 150 operational nuclear warheads that are available for use by a fleet of four Trident SSBNs stationed at the Faslane Naval Base in western Scotland. The UK does not own the missiles, but leases them from a pool of 58 Trident SLBMs shared with the United States Navy. The UK has joined a US programme to extend the service life of the Trident II D5 missile from 2028 until 2042.