On an occasional basis, the Carnegie Endowment publishes translations of Chinese articles on nuclear policy. The aim is to highlight Chinese research for an international audience and give important insights into the thinking of Chinese scholars. These articles, translated by the author, are not Carnegie products and Carnegie does not endorse them or fact-check them. Again, the intention is to provide a window into Chinese discussions.

Does United Kingdom really own an “independent” nuclear force all along? In the context that the European and international security landscapes have experienced a transitional change, how could the UK stick to its pursuance of a nuclear strategy of “deterrence at the lowest possible levels of conflict”? In the face of the continuous development of such technologies as those for space reconnaissance and exploration, antisubmarine, and anti-missile, what should the UK do to ensure the dependability of its nuclear strike capability? And how is the UK going to play “a leading role” in the sector of international nuclear disarmament in today’s world? These are the questions that the article will try to probe into.

The British nuclear strategy stands out quite uniquely. Treading on the heels of the U.S. and the former Soviet Union, Britain conducted its own nuclear tests, becoming the third power in the world to possess nuclear bomb and hydrogen bomb. However, unlike the other nuclear powers, Britain dropped its program of developing independently its own nuclear weapons before long. Moreover, Britain forged a nuclear force with powerful striking capability long ago, yet it has been sticking to a nuclear strategy of “deterrence at the lowest possible levels of conflict” all along when the European and the international security situations underwent a transitional change. Among the five nuclear powers, the British nuclear arsenal ranks last in scale, making it the only nuclear power that has compacted its nuclear capability into a single nuclear weapon system at present, nevertheless it has been making every attempt to play a leading role in the domain of international nuclear disarmament.

The motive for developing nuclear weapons: having in place two nuclear umbrellas

1 Britain harbors a different motive from that of the U.S. in developing nuclear weapons: the American motive is to protect its global security interests with its objects of nuclear deterrence covering Europe and Asia; while the British one is out of the worry for a possible nuclear attack or nuclear blackmail against its own soil. The bitter experience of massive air raid against London during World War II coupled with the agony of witnessing the miserable aftermath of the nuclear strikes against Hiroshima and Nagasaki of Japan woke Britain--both the ruling and opposition parties--up to the vulnerability of its own security. Subsequently, developing a nuclear deterrence capability against the possible nuclear strike by its enemies so as to ensure Britain its national security has become the prevailing thinking of the British decision-making circle.

2 The close of the chapter of World War II saw the U.S. halting cooperation with Britain in the development of nuclear weapons. For the sake of safeguarding its national strategic security, Britain arrived at the decision to develop its own nuclear weapons. At the heels of the U.S. and the former Soviet Union, Britain succeeded in developing its own nuclear bomb in 1952 and hydrogen bomb in 1957, and on that basis, it went a step further to forge its own strategic nuclear strike capability subordinated to its Air Force and nuclear artillery troops subordinated to its Army. Its years of efforts eventually paid off with the acquisition of the capability of developing its own nuclear weapons on its own efforts, thus laying the foundation for further developing its nuclear capability independently.

3 In the last 10 years of the Cold War time, Britain had been procuring “Trident” missiles from the U.S., but keeping them in the American Naval Base located in Kings Bay, with the two countries sharing the service of the missile. The nuclear warhead for arming the missile is designed by the U.S. but manufactured in Britain. However, from the end of 1950s to the later stage of Cold War, the British strategic nuclear weapons system progressively degenerated into jointly developed products of the U.S. and Britain. In July 1958, Britain and the U.S. signed the “Atomic Energy Cooperation Agreement” which obliged Britain to outsource the components of the nuclear weapon system from the U.S. (The period of validity of the agreement has been prolonged to 2014). Not long after that, Britain renounced its guided missile development program and turned around to acquire the delivery system for its strategic weapons from the U.S. Starting from 1962 on, all British nuclear tests were carried out at the testing ground located in Nevada in the U.S. In the same year, Britain and the U.S. signed the “Nassau Agreement”, stipulating that Britain would procure “Polaris” submarine-launched ballistic missile from the U.S. while allowing Britain to produce the submarine and the warheads of the said missile. Following the American offering of the technology for manufacturing nuclear power reactor, Britain set off with the design and production of nuclear-powered submarine by itself. In 1969, the British Royal Navy took over the task of strategic nuclear strike from the Royal Air Force, and thereafter, the nuclear-powered submarine equipped with “Polaris” missiles became the mainstay of the British strategic nuclear forces.In the last 10 years of the Cold War time, Britain had been procuring “Trident” missiles from the U.S., but keeping them in the American Naval Base located in Kings Bay, with the two countries sharing the service of the missile. The nuclear warhead for arming the missile is designed by the U.S. but manufactured in Britain.

Based on the “Nassau Agreement”, Britain’s nuclear capability is considered as an ingredient of the NATO nuclear force, with the U.S. and Britain sharing the control of the “launch key”, thus eventually voiding Britain’s plan of operating nuclear weapons independently. In addition, Britain’s signing of the “Atomic Energy Cooperation Agreement” with the U.S. dismissed all together Britain’s noble ambition of developing nuclear capability independently, thus landing Britain on the track of relying on the U.S. both politically and militarily in the course of time. Interesting enough, the white paper on “The Future of the UK’s Strategic Nuclear Deterrent” issued by the British government in 2006 stated specially that Britain’s nuclear deterrence capability is completely independent of the U.S. in operation; the British Prime Minister alone has the mandate to authorize the usage of Britain’s nuclear deterrence capability when the need comes; and “the nuclear submarine only uses the British code and equipment”, which in fact is a total denial of the allegation that the control of the “launch key” of the British nuclear weapons is shared by the U.S. and Britain. The British government emphasized that the relation with the American nuclear capability had not eroded Britain’s independence in operating its own nuclear deterrence capability, thereby it is sensible to continue the acquisition of components of the nuclear weapon system from the U.S.

The above-stated position of the British government on the issue of an independent nuclear capability reflects the long-standing special strategic relationship between Britain and the U.S. as well as Britain’s unique status in NATO’s nuclear strategy. As matters stand, Britain has set up two nuclear umbrellas for itself, thanks to its move of forming an alliance with both the U.S. and NATO: a). The all-round nuclear deterrence offered by the U.S. and NATO is in the position to respond to the possible massive attack staged by the enemy’s nuclear or conventional forces; b). the “nuclear deterrence at the lowest possible levels of conflict” in the hands of Britain will serve as an alternative in case the former failed. The two umbrellas are mutually complementary strategically with their roles overlapping each other, and yet, each functions in its own different way. Taken together, they can basically answer Britain’s needs of ensuring national security.

4 In the white paper on “the Future of the UK’s Strategic Nuclear Deterrent”, Britain stated specifically that Britain’s retaining the nuclear capability is not motivated by the urge to preserve its international status. However, the British authoritative research institutions and political figures pointed out explicitly that in retaining the nuclear deterrence lies Britain’s vital leverage for bolstering its position as a major power and retaining its sway in international affairs, hence an unappreciated necessity.

The center of achieving nuclear deterrence: to pursue a nuclear strategy of “deterrence at the lowest possible levels of conflict”

In the period spanning from 1947--when Britain arrived at the decision of developing its own nuclear weapons independently, to the mid of 1950s, the British government failed to come up with a firm political guiding thinking in deciding the size of its nuclear force and the application of its nuclear capability. Moreover, the leading circle of the British Armed Forces was even unable to reach a consensus on the issues of formalizing a plan for the development of nuclear weapons and deciding a nuclear strategy. As a matter of fact, the only feasible option left for Britain’s nuclear deterrence strategy was to attack the enemy’s attack-worthy targets such as vital military facilities, political and economic hubs, densely populated areas and hubs of communication.

In the stage spanning from the mid of 1950s to the end of the Cold War, Britain made the tasks of containing the threat of former Soviet Union and ensuring security for both Britain and its NATO allies its nuclear strategic objectives. In addition, Britain intended to develop an integral security shield by relying on the American and NATO’s nuclear capabilities, and make its “independent nuclear deterrence capability” the cornerstone of its own security. The British government once noted that there was no hope for NATO’s conventional military capability to beat back the massive tank attack by Warsaw Pact. For that reason, Britain integrated its strategic and tactical nuclear capabilities into NATO’s overall operation plan of effectuating a “large-scale retaliatory attack strategy” for the sake of deterring the Soviet Union and Warsaw Pact, and discouraging Warsaw Pact headed by the Soviet Union from starting a war against NATO by taking advantage of its superiority in conventional forces.

The dawning of 1960s saw the U.S. and the former Soviet Union reaching a nuclear parity. To avoid being caught in an awkward position of neither being able to start a nuclear war nor being able to launch a limited conventional war, NATO embraced in 1967 a flexible response strategy to the effect that it would put in place a “three-in-one” armed forces consisting of the American and British strategic nuclear capabilities, their tactical nuclear capabilities and NATO’s conventional forces based on the principle of maintaining an effective deterrence on the Soviet Union; that it would resort to the use of nuclear weapons before all others with the aim of preventing the enemy from starting a war; and that in case war flared up, it would make flexible response in accordance with the development of the situation and resort to the use of nuclear weapons when necessary by following the principle of “gradual escalation” so as to ensure the outcome of winning the war.

Unlike the superpowers whose objectives were to scramble for the nuclear cutting-edge or to seek after nuclear parity, Britain came up with the nuclear strategy of deterrence at the lowest possible levels of conflict as early as in the 1960s in light of its national strength and the strategic landscape in Europe then. The primary considerations for formulating such a strategy were the following: Given the unprecedented destructive power of nuclear weapons, no country is ready to endure a nuclear strike—even a limited one, therefore, as long as Britain possessed a limited number of nuclear weapons with reliable survival capability and the capability of reducing the inhabitants on the enemy side as well as their social fortunes into “hostages” or “collaterals”, it would be deterrent enough against the enemy. On the part of the U.S., it would be hardly possible for the U.S. to make a decision of putting its own homeland to the risk of a nuclear attack for the sake of defending Europe. Once the American nuclear umbrella could not be banked on, Britain would be able to resort to its own nuclear capability as the last tool of containment. The British government emphasized that its motive of developing its own nuclear capability was to meet the needs of maintaining a nuclear strategy of deterrence at the lowest possible levels of conflicts, and Britain’s nuclear capability would never be integrated into the START talks between the U.S. and the Soviet Union, nor would it be incorporated into the “Mid-Range Missile Treaty”. For the sake of keeping the effectiveness of its nuclear deterrence, Britain would not promise not to be the first to use nuclear weapons.

To respond to the measurable changes of the security landscape in Europe, the heads of state of NATO adopted the “New Security Concept” in Nov. 1991, confirming that the prime mission of NATO would veer from coping with the Warsaw Pact’s possible military attacks to that of “dealing with crises popping up in multi-fields” instead; that dependence on nuclear weapons would be moderated and it would be left as the last resort; and that the “forward defence” strategy would be dropped, a crack and agile conventional armed forces would be forged, and the mobile combat capability of the troops would be enhanced. Dancing to the same tune, Britain placed emphasis on the nuclear strategy of “deterrence at the lowest possible levels of conflict” to fit in with the new situation and stated that the objective of Britain’s nuclear strategy was to deter the potential aggressors from threatening Britain’s nucleus interests, and nuclear capability would be resorted to only when the utmost national interest was at stake; Britain’s nuclear capability would remain integrated into the collective defense of NATO; and Britain would slash its nuclear weapons substantially and gradually evolve a single nuclear force system consisting of a less number of ballistic missile system launched from submarine.

Britain’s nuclear deterrence position rests on the following five principles: a). The heart of Britain’s nuclear deterrence is to head off nuclear attack. Nuclear weapons are used to deter and to forestall nuclear blackmail as well as to respond to other conducts that encroach upon Britain’s interests, when other measures failed. b). Britain will only retain a nuclear arsenal with the minimum number of nuclear weapons required for bolstering its objective of nuclear deterrence. c). The British government will sedulously cling to a hedging policy on the issue of under what circumstances, in what way and what scale Britain will resort to nuclear weapons, and moreover, Britain will neither declare nor rule out the possibility of being the first to use nuclear weapons. d). Britain’s nuclear deterrence capability will be incorporated into NATO’s overall strategic concept in order to back up the Trans-Atlantic collective security setup. e). Britain’s independent nuclear decision serves to improve the effect of total deterrence of NATO’s nuclear capability, since this practice might be able to dismiss the potential enemy from gambling on that the U.S. or France might stop Britain from launching nuclear attack, thus making them flinching back at the thought of it.

Guiding principle of nuclear capability building: small in size but highly efficient and reliable

British government’s “Strategic Defence and Security Review” issued in Oct. 2010 shed more light on the necessity of retaining a small but highly efficient nuclear deterrence capability as the last resort to forestall ultra-extreme threats. The strategic objectives determined by Britain are: to deter the potential aggressors from posing threat to Britain’s nucleus interests; nuclear capability will be resorted to when the British government deems that its utmost interests are at stake; its nuclear capability will be integrated into NATO’s collective defense; Britain will attain a single nuclear capability system consisting of ballistic missiles launched from submarines; in high-survivability and reliable strike capability lies the key elements of dependability of Britain’s deterrence capability.

Britain conducted 45 nuclear tests and produced 834 nuclear warheads of 8 types from 1953 to 1992. In the time span from 1960s to 1990s, the British nuclear arsenal was basically kept at the level of 250-350 nuclear warheads. Late 1970’s experienced the peak period with nearly 400 pieces of warheads at one point. In the middle of the Cold War, Britain gradually completed its nuclear arsenal consisting of nuclear artillery shells, land-based short-range ballistic missiles, air-based nuclear cruise missiles, depth nuclear bombs and submarine-launched long-range ballistic missiles. In the wake of the disintegration of the former Soviet Union, Britain started unilaterally to scale down its nuclear arsenal by gradually reducing the number of nuclear artillery shells, “Lance” missiles, sea-based tactical nuclear weapons, and nuclear bombs. In addition, all WE 177 nuclear bombshells were destroyed by the end of 1998.

6 To make sure that its nuclear deterrence is dependable, Britain modernized its nuclear weapon system including updating the facilities in the institute for nuclear weapon research located in Aldermaston of Berkshire County, recruiting experts in nuclear weapon technology and improving the production of nuclear warheads. Britain also joined the American program for prolonging the service life of “Trident” missiles, extending their service to 2042. It is expected that the first batch of life-prolonged “Trident D5” missiles will enter service in British Royal Navy by 2020. The technical test for arming Britain’s nuclear submarines with the updated W76-1 warheads has succeeded, which will uplift the precision-strike capacity of Britain’s “Trident” missile and enable it to destroy strong targets like underground bunker.

The white paper on “The Future of the UK’s Strategic Nuclear Deterrent” issued in Dec. 2006 by the British government noted that Britain had already downsized its means of nuclear deterrence to a single system, to wit, single platform, single delivery vehicle and single warhead design; and that Britain’s nuclear arsenal has been pared down by 75% in the aftermath of the Cold War, accounting for less than 1% of the world arsenal and being the country with the least number of nuclear weapons among the five nuclear powers acknowledged by the “Nuclear Non-Proliferation Treaty”. Britain holds the view that land-based system is vulnerable to nuclear attack; air-based system is handicapped by a limited penetration capability and operational radius; and surface-vessel is rather weak in self-defense. In comparison, submarines offers a better platform with the lowest chance of being attacked and ballistic missile has a longer firing range than cruise missile, has a bigger bomb carrying capacity and is difficult to intercept. Out of the consideration of ensuring the effectiveness of nuclear deterrence, the British government eventually made the abovesaid decision.

Britain believes that the following essential elements are required to ensure the effectiveness of deterrence and the dependability of its nuclear capability in responding to dangers and threats: a). Anti-destruction capability and the level of combat readiness, which means to say that its nuclear capability should be able to survive a massive preemptive attack by the enemy and deliver an effective counterattack afterwards; that the nuclear deterrence system is not liable to detection and to being targeted on; and that the nuclear deterrence system is kept at a moderate level of combat readiness all the time. b). The scope of application of the nuclear deterrence capability, which implies that it should be able to meet the requirement of deterring more than one threat coming from any corner of the globe against Britain’s nucleus interests at the same time. c). The scale of nuclear strike and response. Unlike the above two points, a certain degree of uncertainty should be preserved when it comes to the nature and scale of response, so as to offer more options to decide the number of missiles and warheads to be used, and lower the equivalent weight of the warheads, thus enabling Britain to acquire a deterrence capability that is more dependable and can be applied to small nuclear threats.

7 Britain has also arrived at the decision of using the more effective and safe “pressurized water reactor 3” to substitute “pressurized water reactor 2” as the nuclear power system for the new strategic nuclear submarine. The Strategic Defense and Security Review” issued in Oct. 2010 also specified that Britain’s stockpile/operational deployment of nuclear warheads at present stood at <225/<160 pieces respectively but would be cut down to <180/<120 pieces by 2028. Moreover, the missile launching tubes of each of the three strategic nuclear submarines will be lessened from the present 12 to 8 with their nuclear warheads being reduced from the present 48 to 40. In Sept. 2009, Britain declared that its fleet of strategic nuclear submarines would be reduced from 4 to 3, but build 3 more “Agile” submarines to replace the “Vanguard” submarines which will phase out by the year of 2024. It is scheduled to deliver the new strategic submarines in 2028.Britain has also arrived at the decision of using the more effective and safe “pressurized water reactor 3” to substitute “pressurized water reactor 2” as the nuclear power system for the new strategic nuclear submarine. The Strategic Defense and Security Review” issued in Oct. 2010 also specified that Britain’s stockpile/operational deployment of nuclear warheads at present stood at <225/<160 pieces respectively but would be cut down to <180/<120 pieces by 2028. Moreover, the missile launching tubes of each of the three strategic nuclear submarines will be lessened from the present 12 to 8 with their nuclear warheads being reduced from the present 48 to 40.

The review stated that “in keeping an independent nuclear deterrence capability lies the fundamental guarantee for Britain to address the future destabilizing factors and risks. It further asserted that the cardinal challenge that Britain’s nuclear strategy would confront was neither the issue of “independence” since enhancing cooperation with the U.S. in the sphere of nuclear weapon was the path that Britain found it hard to part with in the effort of retaining its nuclear weapon system, nor the pressure that Britain bore in the international nuclear disarmament course because the international community didn’t expect Britain to take the lead to downsize its nuclear arsenal. The cardinal challenge is how to ensure the dependability of its nuclear deterrence. In other words, under the circumstances showing all major world powers are making technological advance constantly in the fields of space reconnaissance and exploration, anti-submarine, anti-missile and all, how to ensure the survival capacity and the strike capability of Britain’s single nuclear weapons system launched from submarines in performing various tasks will be the cardinal challenge confronting Britain.

Britain’s chosen option to use nuclear capability: remaining independent while being corporated into NATO’s overall plan

8 Britain has agreed to allow its nuclear capability being integrated into NATO’s overall defense plan, which means that its nuclear capability will not only be devoted to upholding Britain’s security but also be applied to maintaining its NATO allies security. During the Cold War period, Britain’s nuclear capability was to deter both the possible nuclear strike staged by the former Soviet Union and the possible large-scale attack launched by the conventional forces of the Soviet Union and the other members of Warsaw Pact. In light of NATO’s operational concept of “massive retaliation strategy”, once the Soviet Union was going to launch a large-scale attack or when NATO ascertained that the Soviet forces would launch a large-scale attack, NATO would unfold a preemptive nuclear strike against such targets as the Soviet Union’s vital military facilities, political and economic hubs, densely-populated areas and the hubs of communication, and make every effort to ensure that it would be an operation of quick decision.

Starting from 1960s, NATO introduced an “escalation” operational concept, to wit, that great importance should be attached to putting in place an effective defense with the emphasis being laid on not taking the initiative to provoke a war; and that in case war broke out, NATO was to make a proper and flexible response in light of the scale and nature of the enemy’s attack. NATO posited that the war would be fought in three stages with each stage being divided into a number of rungs. The first stage would be “forward defense” which would unfold with the allied conventional forces deployed at the front trying to check the enemy’s advance. In the meantime, NATO allies would get into the swing of emergency mobilization, marshal and send in reinforcements, and start to conduct counteroffensive operation. Should the first stage fail to do the job, the second stage set in. At this stage, air-ground two-dimensional operation, nuclear warning, and selected and limited tactical nuclear weapon application would be resorted to. If military operation at the second stage was proved inept too at stopping the war, the third stage would begin, which would see a nuclear strike against the Soviet soil. The early stage attack would select some vital targets of the Soviet Union for destruction with limited use of nuclear weapons. And yet, if the war kept on spreading, it would escalate into a full-scale nuclear war. NATO’s “escalation” operational concept aimed at keeping the war at a lower level if possible and making sure that it would enjoy flexibility and the initiative on war options. The “Rogers Plan” developed later by NATO put the emphasis on using its own technical cutting-edge of conventional weapons to offset Warsaw Pact’s numerical superiority in conventional forces and intended to frustrate the enemy’s attack just by resorting to conventional forces, so as to raise the threshold of using nuclear weapons.

When the Cold War drew to a close, the U.S. withdrew all the American nuclear weapons deployed in Britain, implying that the “joint operation” of the American nuclear weapons deployed in Britain—an arrangement reached between the U.S. and Britain in accordance with the “Nassau Agreement”, had come to an end. On its part, Britain set in motion the persistent effort of reducing its nuclear weapons. As a result, the nuclear weapon systems embedded in the British Royal Air Force and Army were decommissioned successively. Consequently, the share of nuclear strike mission born by Britain in NATO’s overall operational concept had shrunk to the level of only being committed to the relevant tasks undertaken by strategic nuclear submarine. Not long after the British and Russian declaration in 1994 to the effect that the two sides would no longer target their nuclear weapons on each other, Britain proclaimed that its strategic nuclear submarine-based missiles would stop leveling at any specific target. Generally speaking, Britain’s continued reduction of nuclear capability is keeping pace with NATO’s underlined advocacy of leaving nuclear weapon as the “last option” in its overall operation scenario.

Over the past half a century and more, Britain sticks to the pursuance of alliance collective security strategy and tries to effect an integration of Britain’s nuclear strategy of “deterrence at the lowest possible levels of conflict” and the alliance collective security strategy by way of incorporating its own national nuclear capability into NATO’s integrated defense system, thus putting in place the foundation stone of Britain’s foreign security policy. Unlike Britain, France emphasized that its nuclear deterrence would only offer nuclear protection for its own country and refused to integrate its independent nuclear capability into NATO’s collective security defense system, nonetheless France put the stress on developing “reasonably sufficient” nuclear deterrence capability which largely share the same meaning as Britain’s nuclear strategy of “deterrence at the lowest possible levels of conflict” though being put in a different way. However, Britain is in much less need to have a large arsenal of nuclear weapons as France does since the former has integrated its nuclear capability into NATO’s nuclear strategy system, and as a result, Britain only retains the single nuclear weapon delivery vehicles, presenting a striking contrast to France who still has to retain such nuclear weapon delivery systems as strategic bombers, strategic nuclear submarines and nuclear–powered aircraft carriers hitherto.

Besides, Britain attaches importance to cooperation with the U.S., France and other NATO allies on the issue of nuclear capability development. For instance, Britain and the U.S. arrived at an agreement in 2006 to jointly develop universal missile components for ballistic missile-launching nuclear submarines of both countries. In addition, Britain will join the U.S. to contrive universal missile compartment/silo(?) for a new type of nuclear submarine. By making use of the American updated W76-1 nuclear warheads, Britain’s nuclear missiles have likewise acquired the precision-strike capability of destroying underground installations. In parallel with this is Britain’s efforts of engaging France in studying the feasibility of technical cooperation over a new type of strategic nuclear submarine, in jointly planning for strategic nuclear submarines of both countries to conduct combat patrol at sea, and in sharing computer simulation data so as to ensure the dependability of nuclear weapons.

The tricky part of nuclear strike policy: painstakingly retaining the ambiguous nature of the conditions that justify a nuclear strike

Britain intentionally sticks to an ambiguous policy on the issue of under what circumstances, in what way and in what scale will nuclear deterrence capability be resorted to. It neither professes nor rule out the possibility of being the first to use nuclear weapons.

9 Britain brought forward the “Sub-Strategic” deterrence concept in its “Strategic Defense Review” in 1998—namely, to ensure that Britain’s strategic nuclear submarine will retain the more agile and dependable nuclear deterrence posture through proper deployment; and that by firing one or a limited number of missiles against the enemy, Britain will be able to send out a political signal, give a warning or display Britain’s resolve of resorting to nuclear weapons when necessary. Britain’s aim of threatening to be the first to use nuclear weapons and to commit nuclear deterrence capability to the fulfillment of sub-strategic missions is to secure more options for it to deter those “rouge states” from using weapons of mass destruction. Officials with Britain’s Defense Ministry once offered the following statement on how Britain commits its strategic nuclear submarine to the fulfillment of both strategic tasks and sub-strategic missions at the same time: To deliver a sub-strategic strike is to use nuclear weapons in a limited and highly selective way, which is clearly different from a strategic strike but carries sufficient punch power to bring those enemies--who miscalculated Britain’s resolve and launched an attack against Britain, to sufficient sense to understand that they must halt their aggression and beat a retreat, or they will be dealt a crushing strategic blow.

However, the sub-strategic concept was dropped from the defense white paper issued in 2006. The then British Defense Minister Mr. Brown stated that Britain never looked to the use of nuclear weapons as a tool to provoke and oppress the other states. Britain’s nuclear weapons were not designed to deal with conflicts and thereby would not be used as such. In the past, “sub-strategic Trident” was intended to imply that nuclear weapons might be used in a limited way, but now Britain inclined to stop using this term. Britain would consider the possibility of using nuclear weapons for self-defense only in the worst-case scenario. But to jump into a conclusion to the effect that Britain has already given up using strategic nuclear submarine for “sub-strategic” missions by basing it just on Mr. Brown’s statement will sound oversimplified and hasty, since Britain also stated in its white paper that in dealing with specific security environment, the low-equivalent nuclear warheads will bring Britain’s nuclear capability up to more dependable deterrence against minor nuclear threats. This means to say that being part of Britain’s strategic nuclear strike capability, the “Trident” missile can be used to carry low-equivalent nuclear warheads and undertake the tasks similar to “sub-strategic” missions.

Maybe it can be understood that the following considerations were behind Britain’s statement of dropping the use of “sub-strategic” concept: For one thing, Britain might think that the concept could result in lowering the threshold of using nuclear weapons, which runs contrary to its much-chanted position of playing a leading role in the field of international nuclear disarmament; for another thing, technology-wise, Britain’s weapons are still not up to the job. In all these years, Britain’s strategic nuclear submarines are armed with large-equivalent nuclear warheads, averaging over 100,000 tons—a fact that badly crippled the feasibility of delivering nuclear deterrence, thus disqualifying them for effectuating the “sub-strategic” strategy which calls for limited and selective use of nuclear weapons. For the sake of procuring low-equivalent warheads, apart from developing its own ones, Britain can try to secure relevant technologies from the U.S. in accordance with their bilateral defense cooperation agreement. The explosion equivalent of the nuclear warheads envisioned by the U.S. for deterring the so-called “rogue states” will be 200 tons or less, and better still, they also have the capacity for destroying military facilities deeply underground. Such low-equivalent nuclear warheads will do much less incidental damage, and thereby can deliver precision-strike against the enemy’s commanding center, hence a deterrent weapon with battlefield combat capability.

In the Cold War time, Britain grounded its nuclear deterrence strategy on the decided condition of resorting to nuclear strike, with the emphasize being placed on using nuclear weapon only as a response to the enemy’s aggressive action. A great number and variety of potential threats facing Britain after the Cold War have driven it to stress on the uncertain nature of security threats and to cope with them by banking on the ambiguous nature of nuclear strike. This is to see to it that the potential enemies can’t be positively certain whether Britain will respond to the threat by resorting to nuclear weapons and render it impossible for the enemies to make a decision, thereby putting the idea of making an attempt on Britain out of the enemy’s head. The defense white paper issued by Britain in 2006 stated clearly that preserving a certain degree of uncertainty is an essential component of Britain’s deterrence posture; and that Britain must not state unequivocally the conditions under which it will resort to nuclear weapons, or else it will be much easier for the potential aggressors to make a decision. The white paper has stated explicitly that Britain will use nuclear weapons against the threats to its “vital interests”; and yet, the definition of “vital interests” (namely the conditions qualifying nuclear strike) has been intentionally left ambivalent with the aim at preserving the effectiveness of the nuclear strategy of “deterrence at the lowest possible levels of conflict”.

10 This is a plain expression to the effect that Britain’s nuclear strategy of “deterrence at the lowest levels of conflict” refuses to rule out the possibility of using nuclear weapon to deal with threats posed to Britain’s vital interests (including threats to Britain’s overseas troops) by non-nuclear states. Despite Britain’s assurance of not using nuclear weapons against non-nuclear states that have signed the “Non-Proliferation Treaty” as stated in its “2010 Strategic Defense and Security Review”, Britain has further stated that this assurance does not apply to any state that has acted against the obligations of non-proliferation; moreover, Britain reserves its right to modify this assurance if countries with weapons of mass destruction constitute a direct threat to Britain and its vital interests. While preserving the ambiguous nature of its conditions qualifying a nuclear strike, Britain refuses to rule out the possibility of unleashing a preemptive nuclear strike against non-nuclear states. The former British Defense Minister Hoon once stated when talking about the situation in Iraq that if the British forces in Iraq were attacked by biological or chemical weapons, Britain may mount a preemptive strike against Iraq. He also indicated that under extreme self-defense circumstances, the British government must be able to articulate the idea of “being eligible to the use of nuclear weapons”.This is a plain expression to the effect that Britain’s nuclear strategy of “deterrence at the lowest levels of conflict” refuses to rule out the possibility of using nuclear weapon to deal with threats posed to Britain’s vital interests (including threats to Britain’s overseas troops) by non-nuclear states. Despite Britain’s assurance of not using nuclear weapons against non-nuclear states that have signed the “Non-Proliferation Treaty” as stated in its “2010 Strategic Defense and Security Review”, Britain has further stated that this assurance does not apply to any state that has acted against the obligations of non-proliferation; moreover, Britain reserves its right to modify this assurance if countries with weapons of mass destruction constitute a direct threat to Britain and its vital interests.

Dr. Henry A. Kissinger pointed out in his article “Nuclear Weapons and Foreign Policy” that deterrence takes the combination of strength, the will to make use of the strength and the assessment of the two factors by potential attackers. It could be safely said that Britain’s nuclear strategy is one based on knowing itself and knowing the enemy. It takes one not only to ascertain enemy’s strategic intention in an active way but also the strategic intention of the allies. All in all, Britain in fact derived its nuclear strategy from Dr. Henry Kissinger’s nuclear deterrence thinking.

Hu Yumin (胡豫闽) is currently serving as a Senior Research Fellow at the China Institute for International Strategic Studies (CIIS) and the China Arms Control and Disarmament Association (CACDA).