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The Nuclear Weapons Dimensions of the 2021 Integrated Review: A First Look

Today’s Integrated Review of Security, Defence, Development and Foreign Policy (IR), Global Britain in a Competitive Age, is said to contain the most comprehensive review of UK nuclear weapons policy since the end of the Cold War (pp.76-78). Although there is certainly some continuity with the 2015 Strategic Defence and Security Review, it sets a decisive course away from the United Kingdom’s long-term trend towards nuclear arms reductions and greater transparency.

Warhead Numbers and Transparency

The most headline-grabbing change to UK nuclear weapons policy is the increase to the cap on its overall nuclear warhead stockpile from 180 to 260, which was leaked last week and is now confirmed. This 44.4% increase decisively moves the Johnson Government away from the pledge made by the Coalition Government in 2010 to limit numbers to not more than 180 by the mid-2020s. While neither confirming that numbers will actually rise nor stating the precise reasons for this change, the IR claims vaguely that the previous target cap must be abandoned due to ‘recognition of the evolving security environment, including the developing range of technological and doctrinal threats’ (p.76). 

A perceived increase in risks, and the implicit fear of long-term vulnerability that accompanies them, is the driving force underpinning the Review. These risks are outlined in the opening paragraph, which cites the fact that some ‘states are now significantly increasing and diversifying their nuclear arsenals … [and] investing in novel nuclear technologies and developing new “warfighting” nuclear systems which they are integrating into their military strategies and doctrines and into their political rhetoric to seek to coerce others’ (p.76). These states seem likely to include not only Russia, but also China, whose force levels are reported to be increasing significantly; the DPRK; and potentially Iran, whose return to the JCPOA is by no means assured.

The IR also states that the Government will ‘no longer give public figures for our operational stockpile, deployed warhead or deployed missile numbers’ (p.77). Such a policy has surely been designed to give defence planners the kind of wiggle room enjoyed by other possessor states and is consistent with the UK’s broader policy of ‘strategic ambiguity’ about when, where and at what scale it would contemplate nuclear weapons use. But it also directly challenges the UK’s longstanding commitment to transparency around these numbers and represents an unfortunate step back for multilateral oversight.

One suspects that the decision to increase the cap and revoke access to deployed numbers has not been taken lightly. The Johnson Government must be well aware of the negative domestic and international publicity this change will bring, and that the impact of this decision may have serious consequences for the global  disarmament and non-proliferation agendas. Although the Government may not see it this way, most Non-Nuclear Weapon States and non-governmental groups will view this decision as the betrayal of an expectation, if not a promise, to continue to cut numbers. The question that’s on everyone’s lips is: what can 260 warheads do that 180 could not?

The timing is particularly unfortunate: announcing an increase in warhead numbers months before the Tenth Non-Proliferation Treaty Review Conference is regrettably reminiscent of the tone-deaf plan to build a new coal mine in Cumbria in the run up to COP26. The Government will have its work cut out to explain increasing the stockpile cap is not a retrograde step to a global audience that in many quarters is pleading for more progress on nuclear disarmament.

For Nuclear Weapons States facing international pressure to disarm, force reductions are often used to evidence that they are indeed engaging in this work in good faith; this becomes that much harder to demonstrate if numbers can simply go up again later. It also becomes significantly harder for a democratic state like the United Kingdom to make a compelling case that other NPT-recognised Nuclear Weapon States like China – let alone those possessor states outside the NPT (India, Pakistan, Israel and North Korea) – should not increase their own force numbers, when the UK itself is planning to do so. The UK has expended significant political capital over the past two decades seeking to manoeuvre themselves into the moral high ground on nuclear disarmament among the Nuclear Weapon States, a position which may now be at risk.

In view of these political costs, it therefore seems likely that the decision was driven by a hard security logic. But what was it? Given the dearth of public domain information available regarding UK nuclear weapons targeting or the state’s assessment of the effectiveness of developing ballistic missile defence technologies on the part of potential adversaries, it’s hard to know exactly what factors were considered or how the final number was reached.

Declaratory Policy 

The United Kingdom’s commitment not to use nuclear weapons against Non-Nuclear Weapon States (its ‘negative security assurances’) has remained unchanged in substance, but the IR provides more detail on the circumstances under which this policy might be revised, adding that ‘future … emerging technologies that could have a comparable impact’ (p.77) to biological or chemical weapons might be sufficient to permit a rethink. This aspect of the Government’s thinking has probably been left deliberately vague, but might include advanced capabilities like long-range precision-strike conventional missiles or drone swarms.

It’s not clear that this rhetorical shift makes a great deal of difference to the UK’s policies in practice or presages further change down the line. The UK already reserves the right to revisit its negative security assurances in light of new information, and one would expect emerging technologies to have already been part of this calculation. But neither is it a sign of progress towards the long-standing calls for the Nuclear Weapon States to gradually reduce and streamline the circumstances in which they would consider the use of nuclear weapons, and thereby reduce the salience of nuclear weapons in their security doctrines.

Rhetorical Shifts

The document makes a number of rhetorical departures from the 2015 Review. For one thing, it adopts wholesale the same language used by NATO to explain why it remains a nuclear alliance: to ‘preserve peace, prevent coercion, and deter aggression’ (p.76). It also brings in the concept of ‘strategic stability’ (p.77), which was not seen in the 2015 Review, although it does not define this further.

The final section gives greater rhetorical prominence to disarmament, arms control, and non-proliferation (although it also lumps together three categories that could each merit a separate section, if prioritised differently). It also strikes a more conciliatory tone towards the nuclear threat reduction community that is centred on trust, mutual security, dialogue, risk reduction and responsibility: all of this is wording that BASIC has used extensively in its publications over the past few years – in particular in our Nuclear Disarmament, Risk Reduction, and Nuclear Responsibilities programmes – as well as other organisations in the UK ecosystem including the European Leadership Network and King’s College London.

Commitments to foster ‘dialogue among states possessing nuclear weapons, and between states possessing nuclear weapons and non-nuclear weapon states, to increase understanding and reduce the risk of misinterpretation and miscalculation’ should be viewed positively. So should the Government’s professed commitment to ensure the UK is a state that ‘takes its responsibilities as a nuclear weapon state seriously and will continue to encourage other states to do likewise’ (p.78). It is only through the practice of these policies and principles that the security context may be improved in time for the next Review.

Will other states believe that these new nuclear policies are driven by the need to respond to a more ‘competitive age’, or by the desire to embody ‘Global Britain’? Certainly they will not go unnoticed. Over the coming months, as the Review Conference approaches, the United Kingdom will need to make the reasoning behind these changes clearer, and demonstrate through its actions – not just its words – its unwavering commitment to advancing the risk reduction and disarmament agendas.

Sebastian Brixey-Williams is the Co-Director of BASIC. Image credit CC 2.0 from Kristina G. at

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