Prepared by theNatural Resources Defense Council

British nuclear forces, 2005

SiNCF BRITAIN WITHDRAW nslast WE 177 gravity bombfrom service in March 1998,it has relied on a single nu-

clear weapon system, its fleetof nuclear-powered ballisticmissile submarines (SSBNs),and their accompanying Tri-dent submarine-launched bal-listic missiles (SLBMs). Thoughthe fleet is expected to be in op-eration until 2020 or beyond,attention is now turning to thequestion of whether Britain re-quires a new generation of nu-clear weapons. The debate is inits early stages, but it has al-ready proved contentious.

Just before he died unexpect-edly in early August, RobinCook, the former foreign sec-retary, called upon Prime Min-ister Tony Blair to "breakfrom the past" and make "thecase that nuclear weaponsnow have no relevance to Brit-ain's defenses in the modernworld." Some suspect Blair hasalready secretly decided tobuild a new generation of nu-clear weapons to replace theTrident system. The debate isunfolding against the back-drop of global concerns aboutnonproliferation, especially inIran and North Korea, andabout Britain's long-standingnuclear "special relationship" with theUnited States.

Any new British nuclear warheadswould be built by the Atomic Weap-ons Establishment (AWE). Since 1950,

the AWE~ has been responsible for thefull life cycle of British nuclear war-heads, from research and developmentthrough disassembly and disposal.

During the 1 982 Falklands War, the British carrier Hermes

(above) transported nuclear depth charges (not pictured}.

British warheads have been designedat Aldermaston, a 750-acre site inBerkshire. Einal assembly and disas-sembly takes place at Burghfield, a225-acre site 7 miles to the east. The

Atomic Weapons Establishment Man-agement Eimited—a joint venture be-tween Lockheed Martin, Serco Eimit-ed, and British Nuclear Fuels, Ltd.—has

a 25-year contract with theMinistry of Defence to operateAWE that is due to expire in2025.

Like its counterpart in theUnited States, AWE is respon-sible for guaranteeing the relia-bility and safety of the war-heads in the stockpile and formaintaining the capability todesign new weapons shouldthe Blair government decide todo so. AWE also supportsarms control treaties to whichBritain is a party. Eor in-stance, its Eorensic SeismologyCentre at Brimpton, near Al-dermaston, monitors earthmovements around the worldto detect underground nuclearexplosions and advises thegovernment on nuclear testingissues.

SSBNs. The current Britishstockpile numbers "fewer than200 operationally availablewarheads," according to theBritish government. This offi-cial terminology implies thatadditional warheads are heldin reserve—as is the case in theUnited States and Russia. Allof these warheads are of one

type, and their sole purpose is armingBritain's SSBNs. The exact type ofwarhead is not publicly known.

The Eabour Party's 1998 StrategicDefence Review (SDR) determined

NOVEMBER/DECEMBER 300b BULLETIN OF THE ATOMIC SCIENTISTS 7 7

Nuclear Notebook

that only one of Britain's four SSBNswould be on patrol at any given time,and it "will carry 48 warheads." TheBritish government reaffirmed thisnumber to Parliament on July 21,2005. The stockpile's remaining war-heads are enough to arm rhe threeother subs, each of which can carry asmany as 16 missiles, with up to three-warheads per missile. Only two of thethree subs would be able to deploy onrelatively short notice; one sub isscheduled to be in major overhaul atall times and would take considerablylonger to deploy, if at all.

The submarine on patrol operates atreduced alerr, with the capability tofire its missiles within days of receiv-ing an authentic launch order (ratherthan within a few minutes, as duringthe Cold War}. The missiles are heldin a "detargeted" mode, meaning thattarget data would need to be loadedinto the guidance system beforelaunch, an operation that takes a fewminutes. It could also take the subsome time to get into position tolaunch a missile. While on patrol, thesubmarine carries out secondary tasks,including hydrographic data collectionand exercises with other vessels. Dur-ing the past few years, a couple ofBritish subs have visited French ports.

Though the government has de-scribed the number of "operationallyavailable" warheads in its stockpile,estimating the size of the total stock-pile remains difficult. There are, how-ever, some hints. The 1998 SDR re-duced the number of Trident II D5missiles to be supplied by the UnitedStates from 65 to 58, meaning thatthere are not enough missiles to fullyarm all four SSBNs. This suggests aRoyal Navy decision to acquire onlyenough missiles to arm three boats(48 missiles), with the remaining 10missiles to be used for spares and test-launches. If we assume that the navyarms each of the 48 missiles with anaverage of three warheads, then only144 warheads are required. It is im-portant to note that there is not a setof Trident Us specifically dedicated toBritish use. Rather Britain draws on a

pool of commingled missiles kept inthe Strategic Weapons Facility At-lantic at Naval Submarine Base KingsBay, Georgia. Britain has title to 58missiles but does not own them; amissile that was deployed on a U.S.sub may later deploy on a British sub,or vice versa.

A second indicator of the size of theBritish arsenal is that Britain assignsits patrolling SSBN a "substratcgicmission" to supplement its strategicrole. Operationally this probablymeans that some of the sub's missileshave a single warhead aimed at tar-gets once covered by WEI 77 gravitybombs. These warheads could beused to attack regional adversaries—so-called rogue states—that haveweapons of mass destruction, a mis-sion that would not require a substan-tial attack. The substrategic missionmay also require smaller warheadyield options. This can be achieved bychoosing to detonate a warhead's un-boosted primary, which would pro-duce a yield of 1 kiloton or less, or bychoosing to detonate the boosted pri-mary, which would produce a yield ofapproximately a few kilotons.

The load-out of an SSBN on patrolwith strategic and substrategic mis-sions would likely be either 10, 12, or14 SLBMs loaded with multiple war-heads; the remaining missiles wouldbe armed with one warhead each. U.S.Trident Us can carry up to eight war-heads; presumably those missiles onBritish submarines can do the same.Assuming a limited upload capability,a few spares, and a number of war-heads always in maintenance (andtherefore not "operationally avail-able"), we conclude that a reasonableestimate of the total stockpile is ap-proximately 200 warheads.

A special relationship. On July 3,1958 the United States and Britainsigned the Agreement for Coopera-tion on the Uses of Atomic Energy forMutual Defense Purposes. For nearly50 years, British and American weap-on designers have worked closely to-gether at each others' labs. BetweenMarch 1962 and November 1991,

British scientists also conducted 24nuclear tests with their U.S. colleaguesat the Nevada Test Site. As a result ofthis cooperation, recent British nucle-ar warheads have been based largelyon U.S. designs. The warhead onBritish Trident missiles is thought tobe a close variant of the U.S. W76warhead.

The tightness of the relationshipmeans that, in part, as the U.S. nucleararsenal goes, so too does Britain's. InApril 2005, a former Eos Alamos Na-tional Eaboratory warhead designerand three colleagues claimed that thereis a serious flaw in the W76 warheadthat could cause it to explode with areduced yield or possibly not at all. Of-ficials from the National Nuclear Se-curity Administration, Eos Alamos,and other experts say there is no prob-lem with the warhead and maintainthat the W76 is reliable, but the issueis of obvious concern to the British.

The British government confirmedin 2002 that staff from the DefenceProcurement Agency's Nuclear Weap-ons hitcgrated Project Team held dis-cussions with their U.S. counterparts"on the U.S. W76 warhead, relevantto the safety and reliability of |Brit-ain's| Trident warhead." In July 2005,the government announced that it in-tends to spend more than £1 billion($1.8 billion) during the next threeyears to ensure the "continued relia-bility and safety . . . of the existingTrident warhead stockpile."

In the United States, such languagehas meant modifying the W76 war-head to incorporate new capabilitiesthat significantly improve the weap-on's effectiveness. The U.S. Navy hasbegun replacing the W76's airburstarming and firing fuzes with a newgroundburst fuze. This modificationsignificantly increases the lethality ofthe W76 warhead and broadens therange of targets that it can hold at riskto include some hard targets, such asreinforced missile silos. Whether Brit-ain also plans to install groundburstfuzes in its warheads is unknown.

Some interesting historical docu-ments about the secret understandings

78 BULLETIN OF THE ATOMIC SCIENTISTS NOVEMBER/DECEMBER 3005

between U.S. presidents and Britishprime ministers on the use of nuclearweapons have heen declassified andpublished on the internet. The docu-ments, which span 1950-1974, revealsome tension in the "special relation-ship." British leaders wanted assur-ances from each new U.S. administra-tion that they would be consulted andhave some say if nuclear weaponswere about to be used. U.S. leaderswanted the freedom to act unilaterallyand never agreed to a British veto onthe use of U.S. forces; they alwaysagreed to consult Britain, but only "iftime permits."

Britain has always had a special rt)lesupporting and collaborating with thedeployment of U.S. nuclear weaponsoverseas. Since World War II, in fact,Britain has based four nuclear-capableU.S. weapons systems, the most nu-merous of which were various gravitybombs, some of which remain onBritish soil today. From 1958 to 1963,the United States deployed 60 Thorintermediate-range ballistic missilesand W49 warheads in Britain; from1968 to 1991, it deployed depthbombs at British bases for use by U.S.,British, and Dutch antisubmarine air-craft; and from 1961 to 1992, U.S.SSBNs used Holy Loch on the Firth ofC'lyde in Scotland as a refit facility.

Nuclear history. Within the lastfew years, interesting new detailsabout Britain's nuclear weapons histo-ry have heen released to the public. Ina two-volimie, 1,100-page official his-tory of the 1982 Falkland Islandscampaign. Sir Lawrence Freedmanprovides specific details about thepresence of British nuclear weapons inthe conflict. In response to Argenti-na's surprise attack in early April,Britain dispatched a task force ofships to the South Atlantic to make astrong diplomatic statement. Two ofthe vessels, the frigates Brilliant andBroadsword^ carried two WE 177 nu-clear depth charges each for killingsubmarines. In London, there was anintense debate over whether to delaythe ships' departure and off-load theweapons, or sail with them and re-

move them later.While en route, the

weapons were transferredto the aircraft carriersHermes and Invincible..which already carried 40and 25 percent, respec-tively, of Britain's nucleardepth charges and werealso traveling to the SouthAtlantic. Only in late Junedid the weapons return toBritain. Freedman stressesthat there was never anyintention to use the weap-ons against the Argentineshut adds that the chief ofthe defense staff, Adm. SirTerence Lewin, was in- ^^^"

ciined to hring them to theSouth Atlantic iust in case Soviet sub-marines got involved in the conflict onthe Argentine side.

In 2003, the British government re-leased information identifying morethan a dozen nuclear weapon acci-dents and incidents since 1960. TheBritish define a nuclear weapon acci-dent as "an unplanned occurrence in-volving the destruction of, or damage,or suspected damage to, a nuclearweapon which has resulted in actualor potential hazard to life or proper-ty, or which may have impaired nu-clear safety." There are two cate-gories of accidents: Category 1, inwhich no release of radioactive mate-rial occurs, and Category 2, in whicha release is detected. Between 1973and 1987, there were seven Category1 accidents and zero Category 2 acci-dents. None of them involved any-thing like the 32 acknowledged U.S."broken arrows'" (accidents), whichinclude airplanes crashing and sub-marines sinking with nuclear weap-ons aboard. In one instance, an ex-plosion inside a U.S. missile silocatapulted a nuclear warhead 600feet into the adjacent woods. Britishaccidents include a few minor trafficmishaps involving vehicles transport-ing nuclear weapons and instances inwhich weapons fell a few inches withno damage to the warheads.

Britain's arsenalSSBNs* Class Date of first patrol

Vanguard

Victorious

Vigilant

Vengeance

SLBMs

Irident II D5

Vanguard

Vanguard

Vanguard

Vanguard

Range

7,400 kilDmeters

December 1994-

•December 1995 1

Jjne 1998 1

Febrjary 2001 ?

No. of warheads x yield

1-3 X lOOkilotons

SSBN: nuclear-powered ballistic missjie submarine; SLBM;submarine-iaurtched ballistic missile. 'Vanguard-class submarinescan carry up to 16 missiles per boat Each SSBN is protected byone or two hunter-killer submarines during transit to and from itspalroi area. British deterrent patrois are ttiougtit to be coordinatedwith the operations of Frencti SSBNs.

The British also track "incidents"—unplanned occurrences that "did notconstitute an accident . . . but which[need] to be reported in the interestsof safety, or because it was likely toattract the attention of the public orthe media." There were 12 such inci-dents between 1960 and 1991. Oneoccurred during the transfer of con-tainers carrying nuclear weapons he-tween warships in the Falklands War.The container was damaged in the ac-cident, but the nuclear weapon wasnot. Another occurred in August 1988when a British warship carrying nu-clear weapons collided with anothership while moored off Hong Kong.Though these ships are not identifiedin British reports, this incident mayhave involved either the carrier ArkRoyal or the transport ship FortGrange., both of which were on over-seas cruises in the Pacific that includ-ed a visit to nuclear-free Australia inOctober. *

Nuclear Notebook is prepared by RobertS. Norris and Hans M. Kristensen nf theNatural Resources Defense Council. Afootnoted version of this article is avail-able online, along with data for all nucle-ar weapon states, at thehitllctifi.org. In-quiries should he directed to NRDC, 1200New York Avenue, N.W., Suite 400,Washington, D.C, 10005; 202-289-6868.

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