United Kingdom and Weapons of Mass Destruction - Nuclear Weapons

Nuclear Weapons

The United Kingdom has four Vanguard class submarines armed with nuclear-tipped Trident missiles. The principle of operation is based on maintaining deterrent effect by always having at least one submarine at sea, and was designed during the Cold War period. One submarine is normally undergoing maintenance and the remaining two are in port or on training exercises.

Each submarine carries up to sixteen Trident II D-5 missiles, which can each carry up to twelve warheads, for a maximum of 192 warheads per sub. However, the British government announced in 1998 that each submarine would carry only 48 warheads (halving the limit specified by the previous government), which is an average of three per missile. However one or two missiles per submarine are probably armed with fewer warheads for "sub-strategic" use causing others to be armed with more.

The British-designed warheads are thought to be selectable between 0.3 kilotons, 5-10 kt and 100 kt; the yields obtained using either the unboosted primary, the boosted primary, or the entire "physics package". The United Kingdom has purchased the rights to 58 missiles under the Polaris Sales Agreement (modified for Trident) from the United States Navy's "pool". These missiles are fitted with United Kingdom-built warheads and are exchanged when requiring maintenance. Under the agreement the United States was given certain assurances by the UK regarding the use of the missiles, however the United States does not have any veto on the use of British nuclear weapons.

The United Kingdom is one of the five "Nuclear Weapons States" (NWS) under the Nuclear Non-Proliferation Treaty, which the UK ratified in 1968.

The UK permits the U.S. to deploy nuclear weapons from its territory, the first having arrived in 1954. During the 1980s nuclear armed USAF Ground Launched Cruise Missiles were deployed at RAF Greenham Common and RAF Molesworth. As of 2005 it is believed that about 110 tactical B61 nuclear bombs are stored at RAF Lakenheath for deployment by USAF F-15E aircraft.

In March 2007, the UK Parliament voted to renew the country's Trident nuclear submarine system at a cost of £20bn. In July 2008, The Guardian claimed that the decision had already been made to replace and upgrade Britain's nuclear warhead stockpile at a cost of £3bn, extending the life of the warheads until 2055.