British Armed Forces,[b] also known as Her Majesty's Armed Forces

Nuclear weapons[edit]

A Trident II SLBM being launched from a Vanguard-class submarine
Main article: Nuclear weapons of the United Kingdom
The United Kingdom is one of five recognised nuclear weapon states under the Non-Proliferation Treaty and maintains an independent nuclear deterrent, currently consisting of four Vanguard-class ballistic missile submarines, UGM-133 Trident II submarine-launched ballistic missiles, and 160 operational thermonuclear warheads. This is known as Trident in both public and political discourse (with nomenclature taken after the UGM-133 Trident II ballistic missile). Trident is operated by the Royal Navy Submarine Service, charged with delivering a 'Continuous At-Sea Deterrent' (CASD) capability, whereby one of the Vanguard-class strategic submarines is always on patrol.^[83] According to the British Government, since the introduction of Polaris (Tridents predecessor) in the 1960s, from April 1969 "the Royal Navy's ballistic missile boats have not missed a single day on patrol",^[83] giving what the Defence Council described in 1980 as a deterrent "effectively invulnerable to pre-emptive attack".^[84] As of 2015, it has been British Government policy for the Vanguard-class strategic submarines to carry no more than 40 nuclear warheads, delivered by eight UGM-133 Trident II ballistic missiles.^[85] In contrast with the other recognised nuclear weapon states, the United Kingdom operates only a submarine-based delivery system, having decommissioned its tactical WE.177 free-fall bombs in 1998.
The House of Commons voted on 18 July 2016 in favour of replacing the Vanguard-class submarines with a new generation of Dreadnought-class submarines.^[86] The programme will also contribute to extending the life of the UGM-133 Trident II ballistic missiles and modernise the infrastructure associated with the CASD.^[87]
Former weapons of mass destruction possessed by the United Kingdom include both biological and chemical weapons. These were renounced in 1956 and subsequently destroyed.