Chapter Four
The Defence Equipment Programme


1. The deployment at the beginning of this year of HMS Victorious, our second Vanguard Class submarine, marks a major step in the transition from Polaris to Trident. Trident has now taken over the main burden of providing our strategic nuclear deterrent, and also provides a continuously-available sub-strategic nuclear capability, a role the Trident force will take over fully when Vigilant enters service and the WE177 bomb is withdrawn in 1998. At that point, Trident will become our only nuclear weapon system.

2. 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.

3. 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.

4. The submarines were designed and built by Vickers Shipbuilding and Engineering Limited at Barrow-in-Furness. Each displaces some 16,000 tonnes submerged, about twice the displacement of the Polaris submarines of the Resolution Class. They are by far the largest submarines ever manufactured in the United Kingdom; a special manufacturing facility, the Devonshire Dock Hall, had to be purpose-built at Barrow for their construction. The Vanguard Class submarines are larger than the Resolution Class mainly because of the need to accommodate the Trident D5 missile. However, the complement of a Vanguard Class boat will be smaller - 132 officers and men compared to a Polaris submarine's crew of 149. The Vanguard Class boats include a number of improvements over previous British submarines, including a new design of nuclear propulsion system and a new tactical weapon system for self-defence purposes. 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, we have made clear that the boats will deploy with no more than 96, and possibly with significantly fewer.

5. Extensive facilities to support the Trident system have been constructed at the Naval Base at Faslane, the home of our strategic nuclear deterrent force, and the Royal Naval Armament Depot at Coulport. These facilities have been designed and built to meet extremely rigorous nuclear safety standards. Unlike the Polaris system, Trident missiles will not be serviced at Coulport but will be returned to the United States Strategic Weapons Facility Atlantic, at Kings Bay in Georgia, for reprocessing at periodic intervals. This more economic arrangement has meant that we have not had to construct our own reprocessing facilities.

6. Some fourteen years after the start of the Trident project, the first submarine, HMS Vanguard, entered service on time in December 1994. HMS Victorious has now repeated that achievement, entering service in December 1995; and work on the final two boats, Vigilant and Vengeance, is proceeding well. The Trident programme has been a considerable technical, scientific and managerial achievement which reflects enormous credit on all those involved. Their work will ensure that we have a credible and effective nuclear deterrent force until well into the next century.