The UK’s Trident Nuclear Programme

Of the “official” nuclear powers (Russia, the US, France, the UK, and China), the UK probably has the most idiosyncratic approach to nuclear deterrence.

But before we discuss the general concept, let’s take a look at the nuts and bolts. At present, the UK’s nuclear deterrence looks as optimised as possible and is based on three mainstays:

– Four Vanguard-class nuclear-armed ballistic missile submarines (SSBNs) built in the UK that provide continuous at sea deterrence (CASD), i.e. the system is organised in such a way that there is always one submarine in the sea (presumably the northeastern part of the Atlantic Ocean) ready to strike at the enemy at any given moment (with one of the other submarines being prepared for combat duty at the base and the other two undergoing maintenance);

– Trident II submarine-launched ballistic missiles (SLBMs) on lease from the US (unused stockpiles are stored at a US naval base with the telling name “Kings Bay”);

– Nuclear warheads, UK-designed (presumably with a number of features that make them close relatives of the US W-76 family), with a yield of around 100 kt (other variants are possible), and “packaged”, it is believed, in warheads similar to the US Mk4/Mk4A family.

There is a steady decline in the total number of warheads. During the latest phase in 2015, the following indicators were enshrined in law: no more than 120 warheads, with a maximum of 40 warheads on patrolling SSBNs.

On the subject of nuclear warheads for UK SLBMs, it is important to note an interesting (albeit officially unconfirmed) fact – while the development of the W76-2 low-yield nuclear warhead in the US gave rise to fairly heated debates on a global scale, the presence of similar warheads in the British Royal Navy’s inventory didn’t particularly bother anyone.

Work is currently underway on a new generation of strategic missile-carrying submarines under the well-deserved name Dreadnought, which should be ready to replace the Vanguard class submarines in early 2030 and provide a “convincing, independent and effective” tool for deterrence in the British arsenal until 2060. The new Dreadnoughts will be equipped with common missile compartments (CMCs) for 12 SLBMs (three sections with four launchers), while the actual load will be eight SLBMs. This component will be identical to that used in the US new-generation Columbia-class SSBN, and London made a significant financial contribution to its development. Incidentally, US partners are also assisting their British allies in the development of a nuclear power plant for the Dreadnoughts.

To date, construction has begun on the first and second SSBNs “HMS Dreadnought” (2016) and “HMS Valiant” (2019), with the third and fourth receiving the equally worthy names of “HMS Warspite” and “HMS King George VI”.

A curious situation emerged in literally the last few months – US officials announced a programme to build new combat equipment for SLBMs under the designation W93/Mk7 (in the language of START, codes beginning with the letter W relate to warheads and Mk to re-entry vehicles), in the context of which cooperation with the UK was explicitly stated. This came as news to experts in the UK, especially as the Ministry of Defence is required to inform parliament of any plans to develop new types of nuclear weapons. Credit where credit’s due, the MoD was very quick to issue a public statement.

Trident missile test launch

Of course, discussions around the adjective “new” when used with nuclear warheads (especially given what I would like to believe is a lack of opportunity to test them by means of a nuclear explosion or indeed any plans to do so) are fascinating in their own right and each side has its own take on the issue, but the situation is nevertheless a clear example of the possible failures in coordinating “near-nuclear” communications even between such close allies. To date, W93 has also given rise to far more questions than it has answers.

It should be noted that the UK’s SSBNs are stationed at the Clyde naval base in Scotland. Brexit notwithstanding, the prospects for an independent (and non-nuclear) Scotland are rather illusory, but the worst-case scenario (for London) is that a new location would have to be found and a new infrastructure built in a very short period of time.

The Concept

The UK’s nuclear doctrine stipulates that unacceptable damage will be inflicted on an enemy in the event of aggression, and there is very little reason to doubt such an eventuality. The country’s nuclear arsenal can be used both independently and as part of NATO’s nuclear forces. Having said that, the Trident’s missiles have not been aimed at specific targets since 1994. At the same time, maintaining a certain amount of ambiguity with regard to something like readiness to launch the first nuclear strike is considered to be a fairly useful way of reinforcing deterrence.

The prime minister is the only person who can give the order to launch a nuclear weapon, although experts believe that the decision would be collegial. Given from a special room in a bunker underneath Whitehall, the order would reach the SSBN through a number of intermediary links, with two people involved in passing on the order at every stage. It is believed that the order could initially be issued from on board the prime minister’s plane, although it would still go through Pindar.

Red button
Red button: This trigger would be used in the final stage of a nuclear missile launch

The fact that the current prime minister, Boris Johnson, was infected with coronavirus once again raised the issue of transferring responsibility for the “nuclear button”. Allegedly, the prime minister can personally appoint up to three “nuclear deputies” within the government, whose identity is kept secret and who would have the right to give commands to nuclear forces in a predetermined order. During the Cold War, the deputies (usually two) included the foreign, defence and home secretaries. Suspended after the end of the Cold War, this procedure was reinstated in 2001. It is probably safe to assume that while Johnson was in hospital, this “deputy” was Secretary of State for Foreign affairs Dominic Raab, who also took over other prime ministerial duties.

In this context, the tradition of the prime minister writing out what action to take and targets to hit in the event of a nuclear war, after which the “letter” is sealed in an envelope and locked in a safe on board the SSBN, is an interesting feature of the way Britain commands and controls its nuclear forces. When a prime minister leaves office, the old orders are destroyed without opening the envelope and new ones are issued (also sealed). It is remarkable that, despite the malady currently plaguing the world of official and sensitive information being leaked, the content of these “envelopes” is still unavailable to researchers. Nevertheless, the possible “options” that the commanding officer of the SSBN could receive in such a situation are as follows: “use nuclear forces”, “don’t use nuclear forces”, “make the most reasonable decision”, and “put yourself under an allied country’s command”.


The Royal Navy is made up of real people, and not only does this lead to drug and sex scandals, it could also jeopardise the CASD policy, given the current COVID-19 pandemic mentioned earlier. In principle, confined spaces, often without access to fresh air, are an extremely suitable environment for the spread of infections, so there are justifiable fears that CASD could face its first break in 50 years. It is important to stress, however, that, in the event of such a scenario, the sick crew would carry out the launch order, if necessary, and a second boat would be prepared for combat patrol duty.

It is not known whether human error led to the failure of the British SSBN during a Trident test launch in 2016 (rumours are that the British crew did everything right and it was the US missile that failed), but the “political dimension” of the situation became very personal. According to media reports, Barack Obama personally asked the then prime minister, David Cameron, not to disclose the details of what happened. Theresa May, who occupied the post soon afterwards, also remained silent. One of the first “victories” of the new cabinet was the successful vote that same summer on the renewal of the British nuclear deterrence programme (which is what eventually became the aforementioned “Dreadnought”). It is difficult to say whether the timely disclosure of information would have changed the situation, but the overall picture isn’t a pretty one (although it is familiar).

hms vigilant
Nine service personnel on HMS Vigilant have been discharged from the Royal Navy after testing positive for drugs

Another important “human” element is the relatively strong anti-nuclear movement in the UK, which occasionally produces extremely interesting documents. The most striking example is probably its report on the consequences of a nuclear attack on Moscow by a Trident submarine. We aren’t going to delve too deeply into the details of this valuable material, only noting that, according to estimates contained in the report, up to half of Moscow’s population would die. Moscow’s missile defence system could handle such an attack, of course, but several UK submarines could launch missiles. It goes without saying that this is a completely hypothetical scenario, but it perfectly demonstrates the destructive power of even such modest (relative to Russia and the US in terms of quantity) nuclear capabilities.

The International Dimension

Unlike France, which is emphatically “independently nuclear”, the UK has always maintained a considerable “international” element to its nuclear development, primarily in terms of its very close cooperation with the US. At the end of 1970, for example, the British were armed with nearly 400 US warheads, including such exotic items as artillery shells and nuclear mines. When it comes to arms control, however, the nuclear capabilities of US allies are traditionally sidelined.

Russian researchers note that keeping the UK out of Russian–US nuclear arms control agreements in conjunction with US SLBMs is an opportunity for “unofficial” Trident test launches. It would seem that, with regard to this long-serving missile, the issue probably isn’t that relevant. When it comes to the new generation of “Anglo-Saxon” SLBMs, however (roughly ready by the end of 2030), it will be possible to discuss new approaches. As such, the issue of multilateral nuclear arms control should not be reduced to the Russia–US–China triangle, of course.

In Britain’s case, the traditionally proposed transparency measures probably seem too modest. And yet, even under these circumstances, the search for uniform approaches to declaratory information on the composition of deployed and non-deployed nuclear forces, test launch notifications and so on could further help the move towards multilateral arms control.

Reposts are welcomed with the reference to ORIENTAL REVIEW.
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