Continuous at Sea Deterrent

The United Kingdom's strategic nuclear deterrent is provided by the Vanguard Class SSBN (Ship Submersible Ballistic Nuclear).

The Royal Navy maintains an at sea deterrent with one of these SSBNs. A credible nuclear deterrent depends upon the ability to threaten an assured and effective response to aggression. For the Royal Navy this is done through the Trident D5 Missile.

Trident D5 Missiles

The Trident II D5 missile has a range of over 4,000 nautical miles and an accuracy, which can be measured in metres. Each missile is technically capable of delivering up to 12 warheads, enabling a number of different targets to be engaged, and each Vanguard class submarine has 16 missile tubes. The missile is ejected from the submarine by high-pressure gas and only when it reaches the surface does the rocket system actually fire.