International Security // Analysis

26 march 2015

The future of the British nuclear deterrent: more of the same?

Matthew Cottee Research Analyst, Non-Proliferation and Disarmament Programme The International Institute for Strategic Studies
REUTERS/Phil Noble/Pixstream
BAE Systems workers stand on a walkway
overlooking HMS Artful, the third of the Royal
Navy's Astute class submarines

In 2016 the British government will have to decide on the future of its nuclear deterrent. Before then however, there is a national election (to be held on May, 7, 2015) to determine the composition of those decision-makers tasked with the job. While it appears likely that the deterrent will undergo modernisation, the issue is gaining more political attention and experiencing heightened scrutiny.

The UK has initiated a process of modernising its nuclear deterrent capability. Its current fleet of nuclear-powered ballistic-missile submarines (SSBN) is approaching the end of its life cycle; the current plan for modernisation involves the like-for-like replacement of these submarines. The UK’s underlying posture will therefore remain one of credible minimum deterrence - the new boats will carry the same Trident II D-5 ICBMs with indigenously built warheads.

The existing four British submarines currently patrol on rotation, ensuring that one is on active duty somewhere in the world at all times. This posture, known as Continuous-At-Sea-Deterrence (CASD) has, as the name suggests, been in constant operation since April 1969. While there is an underlying assumption that Britain will maintain this posture for the foreseeable future, the issue is receiving increased discussion. Although the final decision on whether to commit to the so-called ‘Successor programme’ is to be made in 2016, the government has already started procuring some of the components needed for Successor ahead of its scheduled 2028 service entry.

While other nuclear-armed states are investing heavily in modernising strategic forces, there is a growing public debate about the practicality of nuclear weapons in the UK.

This process of force modernisation is not exclusive to the UK. The Economist this month declared that the world now faces a growing threat of nuclear conflict, with all nuclear powers ‘spending lavishly’ to upgrade their arsenals. In the US for example, the Air Force is in the process of developing a new Long-Range Strike Bomber while the Navy seeks to replace its fleet of Ohio-class submarines. Russia has increased defence spending by 50% since 2007 and has begun testing the Sarmat, a new intercontinental ballistic missile (ICBM). China is developing its fleet of SSBNs and recently tested its JL-2 submarine launched ballistic missile (SLBM). In South Asia, both nuclear powers have recently tested updated delivery systems; India recently demonstrated the Agni-V ICBM and, not to be outdone, Pakistan unveiled its new nuclear cruise missile.

Compared to these programmes however, the British situation is rather different. While other nuclear-armed states are investing heavily in modernising strategic forces, there is a growing public debate about the practicality of nuclear weapons in the UK. With a general election looming in two months’ time, a more visible discussion has emerged about whether the UK’s nuclear deterrent is affordable. Some minor political parties are even questioning whether it is necessary. With early polls suggesting that the result could be another coalition government, the deterrent has become a key policy issue.

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In his most recent response to parliamentary questions, the Prime Minister David Cameron outlined the Conservative stance, asserting that ‘Trident and its replacement are non-negotiable. They are an absolutely vital part of this nation’s security.’ Other parties, such as Labour, are trying to appear amenable to all options, principally maintaining the deterrent posture whilst cutting costs. The Liberal Democrats similarly propose replacing ‘some of the submarines’ but scrapping the policy of CASD. In contrast, the Scottish Nationalist and Green parties are calling for the deterrent to be scrapped completely.

Many of the compromises mentioned by the various parties have already been assessed. In 2011 the Trident Alternatives Review (TAR) was commissioned to determine whether a like-for-like replacement of the existing weapon system was the best choice, or whether the UK could achieve a similar deterrent effect with different postures or equipment, and for less money. The TAR assessed a range of possibilities, from nuclear-capable aircraft to cruise missiles. Although it did not offer specific policy recommendations—nor did it consider unilateral disarmament—it suggested that the existing force structure provides relative value for money, should the UK wish to maintain CASD.

The need for such a posture was argued by David Cameron in 2013, when he explained that maintaining continuous nuclear readiness was important to guard against future unknown threats, particularly from rogue states. Since then, threat perceptions have become more traditional in nature; Russian aggression in Ukraine has reignited Cold War comparisons. While this has served to enhance the arguments of those proponents of British nuclear modernisation, there are also those who have questioned whether the defence budget could be better employed on conventional capabilities instead.

These various concerns provide the upcoming election with added intrigue. The British nuclear deterrent has historically developed a momentum within national strategic thinking that makes it difficult for any government to halt, whatever its political composition. At present it is difficult to foresee any dramatic shifts in the existing posture. However, continued parliamentary debate on the issue suggests that the practicality of British nuclear weapons will continue to be subjected to enhanced scrutiny. Furthermore, future decisions are likely to be increasingly politicised, framed by the domestic context in addition to perceptions of international threat.

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Matthew Cottee, “The future of the British nuclear deterrent: more of the same?,” Russian International Affairs Council, 26 March 2015,

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