Trident (UK nuclear programme)

Trident is the United Kingdom's current nuclear weapons system. It consists of four Vanguard-class submarines, each armed with up to eight Trident II D5 submarine-launched ballistic missiles (SLBMs). The missiles are capable of delivering independently targetable nuclear warheads.

The Trident programme replaced the earlier Polaris system and became operational in 1994. The purpose of Trident, as stated by the UK government, is to deter the most extreme threats to national security, which cannot be deterred by other means. This is achieved through a policy of "credible minimum deterrence," meaning the UK maintains a nuclear force sufficient to deter potential aggressors without seeking numerical parity.

The Vanguard-class submarines are based at HM Naval Base Clyde (Faslane) in Scotland. The Trident II D5 missiles are leased from a shared pool maintained by the United States, which also uses the same missile system. The warheads are designed, manufactured, and maintained by the United Kingdom's Atomic Weapons Establishment (AWE).

The UK government has repeatedly affirmed its commitment to maintaining a continuous at-sea deterrent (CASD), meaning that at least one Vanguard-class submarine is always on patrol. The Trident programme and the UK's commitment to nuclear deterrence remain a significant issue of political and public debate, focusing on its cost, ethical considerations, and strategic effectiveness. Debate includes potential alternative systems and the UK's obligations under the Treaty on the Non-Proliferation of Nuclear Weapons (NPT).