Ernest J. Moniz and APLN member Des Browne respond to the UK government’s announcement on policy changes to increase nuclear weapon stockpile and to no longer publish details of operational stockpile, deployed warhead or deployed missile numbers, all of which go against UK’s leadership role on nuclear disarmament and the Biden administration’s global commitment to reduce nuclear risks. Read more.

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London has inexplicably abdicated its longstanding leadership role on nuclear disarmament by announcing a policy change that runs counter to President Biden’s commitment to reduce the role of nuclear weapons in national security policies.

This was an unforced error, adding a thorn in the side of the Biden administration at a time when the UK-US “special relationship” is particularly important. The opportunity for co-operating on a bold transatlantic policy to reduce global nuclear risks needs to be recaptured.

In an abrupt change of course, the UK government announced it will increase the cap on its nuclear weapon stockpile by 15 per cent from the current level of 225 — and 44 per cent from their plan to reduce to 180 by the mid-2020s — to no more than 260 warheads. This decision represents a significant reversal from the long-standing position in the UK on reducing the number of nuclear weapons while maintaining a minimum deterrent force.

Equally concerning is the decision that the UK will no longer publish details of its operational nuclear stockpile, deployed warheads and deployed missile numbers, a blow to nuclear transparency. The US and Russia both declare the numbers of their deployed strategic warheads and delivery vehicles.

The public justification provided by London for this nuclear about-face is, so far, thin and unconvincing. The broad review of security, defence, development and foreign policy lacks a compelling rationale for increasing the warhead cap, making only a brief reference to an “evolving security environment, including the developing range of technological and doctrinal threats”.

In part, this is probably a reference to Russia’s new and planned nuclear systems, but no explanation is given for how increasing the number of warheads in the UK stockpile will provide a more credible deterrent, improve the security of the UK and its Nato allies or in any way impress Moscow—whose nuclear force will continue to dwarf Britain’s.

The UK’s nuclear move explicitly reserves the right to threaten nuclear use if a threat from chemical and biological weapons or the new caveat of “emerging technologies” make it necessary. What does this really mean? Whether the UK policy shift is proportionate to the threat is debatable, but under any circumstances, is it credible? Would the UK ever seriously use a nuclear weapon against a chemical, biological, or cyberattack?

An expanded use policy for nuclear weapons runs directly counter to Biden’s longstanding commitment to consult with allies about moving towards a more restrictive “sole purpose” declaratory policy under which the nuclear arsenal would be used only for deterring or retaliating against nuclear attacks on the US and its allies including the UK.

Coming just months before the Nuclear Non-Proliferation Treaty (NPT) Review Conference—the international gathering where countries assess their mutual progress on meeting the goals of the treaty—this announcement undercuts the UK’s strong record of leading on nuclear non-proliferation, disarmament and transparency. The UK has long prided itself on its commitment to the NPT, including the obligations of the nuclear powers to pursue nuclear disarmament.

It has been, alongside the US, a champion for P5 (China, France, Russia, UK, US) transparency about nuclear forces and doctrine. The UK position now complicates efforts to encourage greater transparency on the part of Russia and especially China. Moreover, by announcing an increase in the cap on its nuclear stockpile, the UK has virtually guaranteed Russia will demand that the UK stockpile (and that of France) be counted when the US and Russia consider further nuclear reductions; it also could undercut calls for China to cease its nuclear buildup.

Coming weeks after the welcome announcement of the US and Russia to extend the New START treaty and to engage in successor agreement discussions, the UK decision flies in the face of the renewed opportunity to stop the nuclear arms race and reinvigorate dialogue on additional reductions and other steps to reduce nuclear risks. The UK declaration presents a significant bump in the road for the Biden administration, when its closest ally moves in a contrary direction.

The UK announcement makes US leadership on disarmament and co-operation between London and Washington on nuclear policy and programmes potentially more difficult but no less important. The Biden administration is just beginning its review of policy and the nuclear modernisation programme, including whether to continue pursuing the W93, an expensive new US warhead proposed during the Trump administration that would, if pursued, guide the development of Britain’s new warhead.

The UK’s deterrent has always been heavily reliant on the US, both for the missiles used on submarines and to some extent the warheads they carry. Hence the necessity of close co-ordination and no surprises, including on significant nuclear policy announcements such as this one.

The UK-US relationship is and will remain “special”, but the UK’s new nuclear policy opens a fault line in need of rapid repair. As the Biden administration resumes global leadership to reduce nuclear risks, its closest ally must be inspired to redouble its commitment to this cause.

Ernest J. Moniz is co-chair and CEO of the Nuclear Threat Initiative and was US secretary of energy under Barack Obama 2013-17; Lord Browne of Ladyton (Des Browne) was UK defence secretary, 2006-08