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Further Reading

Trident-II D-5

In July 1980 the U.K. requested, and the U.S. agreed to, the sale of Trident I missiles (less warheads), equipment, and services to the U.K. On 30 September 1980, the U.S. and U.K. letter agreements were formally implemented by an exchange of diplomatic notes that incorporated the TRIDENT sale into the POLARIS Sales Agreement.

In light of the U.S. DoD decision to develop and procure the TRIDENT II (D5) missile, the U.K., in order to maintain commonality with the U.S., requested in March 1982 that the U.S. sell them the TRIDENT II instead of the TRIDENT I. The U.S. agreed to this substitution in an exchange of letters between President Reagan and Prime Minister Thatcher.

The Director, SSP, is the U.S. project officer for this program, and the Chief Strategic Systems Executive (CSSE) is the British project officer. A small British staff from CSSE is assigned to SSP, and a U.S. liaison officer from SSP is assigned to duty in the British Ministry of Defense to ensure prompt and effective support to the U.K. programs. A Joint Steering Task Group, chaired by the respective Admirals in turn, meets alternately in London and Washington three times a year.

The Trident D5 missile is a three-stage solid-fuel rocket approximately 13 metres long, over two metres in diameter and weighing 60 tonnes. It has a range of over 6,000 kilometres. Each missile is technically capable of carrying up to twelve warheads and delivering them on to different targets with an accuracy that can be measured in metres. The advanced capabilities of the system enable it to carry out both the strategic and sub-strategic roles.

On 11 March 1982, agreement was reached between the U.K. and the U.S. to purchase the TRIDENT II missile system. The procurement of D5's replaced the U.K.'s original request of 10 July 1980 to procure C4's.

Although the Trident missiles are being bought from the United States, their warheads and the submarines that carry them are British designed and built. The warheads are designed by the Atomic Weapons Establishment at Aldermaston and assembled at Aldermaston and Burghfield.

The Vanguard Class submarines are larger than the Resolution Class mainly because of the need to accommodate the Trident D5 missile. The 16-tube missile compartment is based on the design of the 24-tube system used by the United States Navy's Ohio Class Trident submarines. Although each Vanguard Class submarine is capable of carrying 192 warheads, the boats will deploy with no more than 96, and possibly with significantly fewer.

The TRIDENT II (D5) Life Extension Program extends the service life of the TRIDENT II (D5) Strategic Weapons System to support the extended service life of the OHIO Class Submarine to 45 years. This program, the result of a Navy/OSD study, is designed to extend the production and sustain the effectiveness of the TRIDENT II Strategic Weapons System to 2042. The 2001 Nuclear Posture Review (NPR) supported full funding for D5 Life Extension and the Navy revalidated this low rate production continuity acquisition strategy in a report to Congress in 2002. The TRIDENT II (D5) Life Extension Program will be accomplished through upgrades to missile and guidance electronics to mitigate obsolescence, and through the continued production of critical missile components.