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Table of British Nuclear Forces, 2002

Weapon System




x yield

No. in


Trident II D-5
1-3 x 100 Kt
# average loading five warheads per missile, some missiles carry one warhead , various yield options


We estimate the current British stockpile at about 200 of one type. The British stockpile peaked in the mid-1970's at some 350 warheads.

In July 1998, the Blair Government announced the results of the Strategic Defence Review (SDR). The decisions with regard to the British nuclear forces were:

  • Only one SSBN will be on patrol at any time, carrying a reduced load of 48 warheads-half the Conservative Government's announced ceiling of 96.

  • The submarine on patrol will be at a reduced alert state and will carry out a range of secondary tasks; its missiles will be detargeted, and after notice the SSBN will be capable of firing its missiles within several days rather than within several minutes, as during the cold war.

  • There will be fewer than 200 operationally available warheads, a one-third reduction from the Conservative Government's plans.

  • The number of Trident II (D-5) missiles already purchased or ordered from the United States was reduced from 65 to 58.

As a result of these decisions the total explosive power of the operationally available weapons will be reduced by over 70 percent compared to what was proposed. The explosive power of each Trident submarine will be one-third less than that of the four Chevaline-armed Polaris submarines, the last of which was retired in 1996.

British warheads are designed at Aldermaston a 670 acre-site in Berkshire. Final assembly takes place at Burghfield, a 270-acre site seven miles to the east. The component manufacturing facility at Cardiff was closed in February 1997 after 36 years and its functions were transferred to Aldermaston and Burghfield. Approximately 3,600 people are employed at the two facilities. On-going maintenance of the warheads takes place at Burghfield as does disassembly. By March 2002 the last of the Chevaline warheads were scheduled to be dismantled.

The RAF operated eight squadrons of dual-capable Tornado GR.1/1A aircraft. At the end of March 1998, with the withdrawal of the last remaining WE177 bombs from operational service, the Tornadoes' nuclear role was terminated, bringing to an end a four decade long history of RAF aircraft carrying nuclear weapons. By the end of August 1998 the remaining WE177 bombs had been dismantled. The Tornadoes currently at RAF Bruggen in Germany will be reassigned to RAF Lossiemouth and RAF Marham in the UK by the end of 2001, and the base at Bruggen will be closed.

In April 2000 the Ministry of Defence (MOD) awarded a contract for 10 years of operation of the Atomic Weapons Establishment (AWE) to an industrial consortium consisting of Lockheed Martin, Serco Limited and British Nuclear Fuels. The amount of the contract was 2.2 billion ($3.6 billion). On 1 April 1999 the Chief of Defence Logistics assumed overall responsibility for the routine movement of nuclear weapons within the UK. Day-to-day duties are being transferred, in phases, from Royal Air Force (RAF) personnel to the Ministry of Defence (MOD) Police, with support from AWE civilians and the Royal Marines. The process will occur gradually and be completed by March 31, 2002.

The first submarine of the new Trident Class, the HMS Vanguard, went on its first patrol in December 1994. The second submarine, Victorious, entered service in December 1995. The third, Vigilant, was launched in October 1995 and entered service in the autumn of 1998. The fourth and final submarine of the class, Vengeance, was launched on September 19, 1998 and commissioned on November 27, 1999 at the Marconi-Marine Shipyard in Barrow-in-Furness. The Royal Navy announced in February 2001 that the Vengeance entered operational service with the First Submarine Squadron began its part of the cycle of patrols. The Vanguard Class submarine has a total complement of 205 to provide a Ship's Company of 130 for a patrol. The current estimated cost of the program is $19.8 billion (13, 662).

Each Vanguard Class SSBN carries 16 U.S.-.produced Trident II (D-5) SLBMs. There are no specifically U.S. or British Trident II missiles but a pool of SLBMs at Strategic Weapons Facility Atlantic at the Kings Bay Submarine Base, Georgia. The UK has title to 58 SLBMs but does not actually own them. A missile that is deployed on a US SSBN may at a later date deploy on a British one, or vice versa. British SSBNs conduct their missile flight tests at the U.S. Eastern Test Range off Florida. The Vanguard conducted two successful Demonstration and Shakedown Operations (DASO) in May and June 1994, launching two missiles. The Victorious held its DASOs in July and August with two missiles fired. In October 1997, the Vigilant launched two missiles during two DASOs, and finally on September 21, 2000, the Vengeance launched a Trident II D5 during a single DASO exercise.

Of the four SSBNs, one is normally on patrol at any given time. Two more submarines are undergoing training in port or in local waters and could be deployed with relatively short warning. A fourth submarine is undergoing repair and maintenance and would require significantly longer preparation to be able to deploy. Each SSBN is protected by one or two hunter killer submarines (SSNs) during transit to and from its patrol area. In the fall of 2000 the Royal Navy briefly withdrew all SSNs from service after the Tireless suffered a reactor malfunction. While the submarines were being checked for similar reactor problems, other anti-submarine warfare (ASW) assets such as frigates, ASW helicopters, and maritime patrol aircraft were used to guard survey transit areas around the shallow waters of the Irish Sea. British deterrent patrols are thought to be coordinated with the operations of French SSBNs.

Reducing the number of RVs can extend the range of a missile. In its "sub-strategic" configuration, for example, a missile carrying a single warhead would have a range of more than 6,000 miles.

British SLBMs are thought to carry a variation of the U.S. W76 warhead designed for Trident I C4 and Trident II D5, enclosed in a U.S. Mk-4 reentry vehicle.

Several factors enter into the calculation of the number of warheads that will be in the future British stockpile. It is assumed that the UK has produced only enough warheads for thee boatloads of missiles, a practice it followed with Polaris. As stated in the SDR, there will be 'fewer than 200 operationally available warheads' in the stockpile and no more than 48 warheads per SSBN. If all four SSBNs were fully loaded (MIRV x 3) that would total 192 warheads. The government also stated that it would be the practice that normally only one SSBN will be on patrols, with the other three in various states of readiness.

A further consideration is the "sub-strategic mission." A MOD official described it as follows: "A sub-strategic strike would be the limited and highly selective use of nuclear weapons in a manner that fell demonstrably short of a strategic strike, but with a sufficient level of violence to convince an aggressor who had already miscalculated our resolve and attacked us that he should halt his aggression and withdraw or face the prospect of a devastating strategic strike." (RUSI Journal, 1996). The sub-strategic mission has begun with Victorious and "will become fully robust when Vigilant enters service," according to the 1996 White Paper. Vigilant achieved Operational Availability on February 1, 1998. If this has remained the policy then some Trident II SLBMs already have a single warhead and are assigned targets once covered by WE177 gravity bombs. Therefore it follows that when Vigilant is on patrol, 10, 12 or 14 of its SLBMs may carry up to three warheads per missile, while the other 2, 4 or 6 missiles may be armed with just one warhead. There is some flexibility in the choice of yield of the Trident warhead. (Choosing to only detonate the unboosted primary could produce a yield of 1 kiloton or less. Choosing to detonate the boosted primary could produce a yield of a few kilotons.) With these two missions a SSBN would have c. 36-44 warheads on board during its patrol.

The table assumes that the future British stockpile for the SSBN fleet will be ca. 160 warheads. With an additional 15 percent for spares, the number that are, "operationally available" is estimated to be some 185 warheads. Another fifteen warheads or so are probably in some stage of maintenance and are not "operationally available" and thus the total stockpile is probably around 200 warheads. At any given time the sole SSBN on patrol would carry approximately 40 warheads. The second and third SSBNs could put to sea fairly rapidly, with similar loadings, while the fourth might take longer because of its cycle of overhaul and maintenance.

last revised 11.25.02

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