Albion and the Apocalypse

The Royal Navy's UGM-133A SLBMs are expected to be mainstay of the British nuclear deterrent for the foreseeable future.

Upon becoming the United Kingdom’s prime minister on 13 July Theresa May, like her predecessors, was asked to write several letters by the cabinet secretary Sir Jeremy Heywood, the country’s most senior civil servant.

Every prime minister since Edward Heath (1970 to 1974) has performed a similar task, following the UK’s adoption of the Lockheed Martin UGM-27 Polaris A-3 Submarine Launched Ballistic Missile (SLBM), up to 16 of which were accommodated on each of the Royal Navy’s four ‘Resolution’ class nuclear-powered ballistic missile submarines (SSBNs), entering service since 1968. The letters drafted by Ms. May and her predecessors are known as the Letters of Last Resort. According to open sources, Sir Jeremy would have briefed the prime minister advising her of the destructive power of each of the Lockheed Martin UGM-133A Trident-D5 SLBMs carried by the Royal Navy’s four Vickers Shipbuilding and Engineering/BAE Systems ‘Vanguard’ class SSBNs, are be capable of inflicting.

Each ‘Vanguard’ class boat can carry up to 16 missiles, according to the UK MoD and one boat is always on patrol in accordance with the UK’s Continuous At Sea Deterrence policy. Open sources differ, but the UGM-133A’s Mk.4/4A (also known as the Trident Holbrook) warhead may have a yield of between 80 and 100 kilotons/kt (one kiloton equals 1000 tonnes of conventional explosive), and there has also been some speculation that smaller warheads maybe available for the missile providing a yield of between ten and 15 kilotons. A crude simulation, courtesy of the website of a 100 kiloton airburst detonation of such a warhead (all UK warheads are reportedly designed only for airburst detonation) above the Russian city of Severomorsk, in the northwest of the country, shows that 35500 people would be killed instantly, with a further circa 16400 injured.

The Royal Navy ‘Vanguard’ class SSBNs, an example of which is pictured here, are now in the twilight of their careers.

The Letters of Last Resort are written in private by the prime minister. Each letter is handwritten and contains an identical instruction regarding the course of action that the Captain of each ‘Vanguard’ boat is to perform, if they believe that a nuclear attack has destroyed the British government, and killed or otherwise incapacitated the prime minister and their deputy, assumed to be an unnamed member of the prime minister’s cabinet. Once the letters are written they are placed in a sealed envelope, and each letter is placed within a safe, within the control room of each of the ‘Vanguard’ boats. Once the prime minister leaves office, these letters are destroyed unopened. Thus the only person who knows what course of action they would have recommended to the Captain is the prime minister themselves. Whether previous prime ministers would have ordered the Captains to launch all their missiles to deliver a devastating retaliatory strike, to deliver a partial strike, place the submarine at the service of an ally or hold their fire, is unknown. Only one prime minister has given a clue as to the course of action they recommended. James Callaghan, the UK’s prime minister between 1976 and 1979 disclosed in a 1988 television documentary: “If we had got to that point where it was, I felt, necessary to do it, then I would have done it (ordered the missiles to be used).” However, he added that: “I’ve had terrible doubts of course about this. And I say to you that if I had lived after having pressed that button, I would never, never have forgiven myself.” Asking any person to write down their intentions regarding such explosive power concentrates the mind to say the least. According to Professor Peter Hennessy, Attlee professor of contemporary history at Queen Mary University of London, speaking in the 2008 radio documentary The Human Button, when prime minister Tony Blair (1997-2007) was asked to write his four letters; “became quite quiet.”


Ms. May’s letters will be placed in the safes onboard the four ‘Vanguard’ class boats as and when they are in port, replacing those of David Cameron, who resigned as prime minister on 13 July in the wake of the United Kingdom voting to leave the European Union. Yet the ‘Vanguard’ class SSBNs are now in the twilight of their years, having entered service in 1993, the four boats; HMS Vanguard, HMS Victorious, HMS Vigilant and HMS Vengeance are expected to retire from circa 2030. These boats will be replaced with a new class of SSBNs built by BAE Systems. On 20 October the UK secretary of state for defence Sir Michael Fallon, revealed that the new SSBNs which had previously nicknamed the ‘Successor’ class, since May 2011, when the UK government decided to commence the initial assessment phase for a new class of SSBNs to equip the Royal Navy, would be called the ‘Dreadnought’ class.

Work on the ‘Dreadnought’ class is continuing. A statement provided to Armada from the UK MoD stated that the “vast majority of the (SSBN) design will be frozen over the next two-to-three years.” The statement added that: “Given the ‘Dreadnought’ class is a completely new submarine design there are a combination of technological advances, for example in electronic systems driven by the civilian market.” Other important design developments include “increased modularity for ease of build, test and commissioning and a design which can accommodate mixed male and female crewing.” Regarding schedules, the UK MoD told Armada that it expects the first ‘Dreadnought’ class SSBN to leave BAE Systems’ construction facilities in Barrow-in-Furness, northwest England, “in the late 2020s,” and to enter service in the early 2030s. Follow-on boats are scheduled to be built by the 2040s.” To date, the firm has received $1.6 billion of funding for the SSBN’s construction, the UK MoD continues, and around 100 contracts have been awarded covering the ‘Dreadnought’ class’ development.

The UK government has taken the decision to replace the Royal Navy’s existing ‘Vanguard’ class SSBNs with the new ‘Dreadnought’ class boats, one of which is depicted in this artists’ impression. (UK MoD)

The UK Ministry of Defence has taken the decision to retain the same UGM-133A SLBMs onboard the new SSBNs, but to outfit the new SSBNs with a new Rolls-Royce PWR-3 pressurised water reactor; the preceding PWR-2 reactor currently outfitting the ‘Vanguard’ and BAE Systems’ ‘Astute’ class SSBNs and nuclear-powered attack submarines. Alongside the new submarines, the UGM-133A SLBMs will receive modernised warheads. A request under the UK’s Freedom of Information Act regarding the UGM-133A published on the UK MoD’s website in August 2015 stated that an initiative is now underway to upgrade this warhead to the Mk.4A status. The letter continues that: “The Mk.4A arming, fuzing and firing system is a non-nuclear component being introduced into the UK Trident warhead to replace similar (components) which (are) becoming obsolete.” A further clarification issued by the UK MoD stated that “a replacement warhead (for the SLBMs) is not required until at least the late 2030s or possibly later.”

The Royal Navy’s UGM-133A SLBMs are expected to be mainstay of the British nuclear deterrent for the foreseeable future.


That said a decision will still be required from the UK Houses of Parliament to give the go-ahead for the development and production of the new warhead. The statement continued that: “Given lead times, however, a decision on replacing the warhead may be required in this Parliament (which will be dissolved by 7 May 2020 prior to the General Election) or early in the next.” The UK MoD told Armada that: “A replacement warhead will not be required until at least the late 2030s, possibly later.” Any replacement warhead is expected to include some design enhancements such as the capability to hit targets with an accuracy in excess of the current 80 metres (262.5 feet) which the existing Mk.4/4A warhead is believed to be capable of achieving, according to David Cullen, a researcher at the Nuclear Information Service, a Non-Governmental Organisation (NGO) based in Reading, western England. Evidence given to the House of Commons Defence Select Committee, which overseas the UK MoD and the country’s armed forces, by the Nuclear Information Project, an initiative of the US Federation of American Scientists, based in Washington-DC in February 2007 estimated the UK to be in possession of between 150 and 170 warheads, with the UK in possession of 58 UGM-188A SLBMs according to open sources.

The ‘Dreadnought’ class will continue to carry the UGM-188A SLBM. The UK MoD statement provided to Armada states that: “Like the ‘Vanguard’ class SSBNs, the ‘Dreadnought’ class will carry the current Trident-D5 missile and there are no plans to replace these.” That said, the lifespan of these missiles are expected to be increased and “The UK is working with US partners in a programme to extend the lifespan of the D5 missile to the 2060s.”

The parliamentary decision which will be required regarding the replacement of the Mk.4A warhead underscores the political challenges which the ‘Dreadnought’ class programme still faces. Unsurprisingly, the UK’s possession of nuclear weapons is a controversial subject. A poll commissioned by The Independent newspaper this January revealed that 51 percent of those interviewed backed the renewal of the Trident weapons system (submarine, missiles and warheads). Yet, Jeremy Corbyn, the leader of the opposition Labour Party, remains opposed to the UK’s possession of nuclear weapons. In September 2015, he told the British Broadcasting Corporation: “I am opposed to the use of nuclear weapons. I am opposed to the holding of nuclear weapons. I want to see a nuclear-free world, I believe it is possible.” The opinions of his party are more nuanced. On 19 July, Members of Parliament (MPs) voted on whether the UK should renew the Trident weapons system. Ms. May’s government won the vote with 472 MPs supporting the government’s plans, with 117 voting against, including Mr. Corbyn. Interestingly, 140 of Labour’s 230 MPs voted in favour of replacing the weapons system. Should a vote be taken before the end of the current parliament on whether to replace the Mk.4A warhead, Ms. May’s government could rely on similar levels of support from the Labour opposition in the House of Commons to ensure that this initiative goes ahead.

The Scottish Question

Yet challenges to the Trident renewal also come from other quarters. As Dr. Nick Ritchie, a senior lecturer and expert in the UK nuclear deterrent in the Department of Politics at the University of York, northern England notes: “There are two outstanding issues that have shaped the debate (regarding the replacement of the Trident weapons system). The first is the independence of Scotland.” The Scottish National Party (SNP) is resolutely against the UK’s ownership of nuclear weapons. The SNP’s website states that: “the case for Trident is non-existent … It’s wrong, morally and financially.” Of the 117 voting against the Trident renewal on 19 July, 58 of the MPs were from the SNP, with the party stating that: “56 percent of those living in Scotland oppose the renewal of Trident.” The position of the SNP, which is the largest party in the Scottish Parliament, is highly significant to the future of the UK’s nuclear deterrent. Scotland is home to Her Majesty’s Naval Base (HMNB) Clyde to the west of Glasgow on the River Clyde, which is the home base of the ‘Vanguard’ class, and the Royal Naval Armaments Deport (RNAD) Coulport on Long Loch, western Scotland which is where the Mk.4A warheads are stored and loaded into their UGM-133A SLBMs before and after an SSBN patrol.

The future of the UK’s nuclear weapons in Scotland is now complicated by two distinct, but related factors. The first the future of Scotland in the United Kingdom: A referendum on independence for Scotland held on 18 September 2014 saw 55 percent of Scottish voters reply ‘no’ to the question: “Should Scotland be an independent country,” posed to them. Meanwhile, the referendum on whether the United Kingdom should remain in the European Union (EU) which was held on 23 June saw 51.8 percent of British votes cast expressing a preference to leave the EU. Nevertheless, Scotland voted 62 percent in favour of remaining in the EU. The second outstanding issue shaping the debate, Dr. Ritchie adds, is the “nature of the Brexit (as the UK’s decision to leave the European Union is dubbed) settlement.” The SNP is strongly supportive of the EU and its leader, and Scotland’s First Minister Nicola Sturgeon, the leader of the Scottish government, has stated in the past that: “the EU is not perfect, but Scotland’s interests are best served by being a member.” Ms. May is now expected to trigger Article 50 of the Treaty of Lisbon, which forms the constitutional basis of the EU, to initiate the UK’s formal departure from the supranational organisation. Speaking in February, Ms. Sturgeon told the BBC that: “if … we find ourselves, having voted to stay in the EU, being taken out against our will, I think there will be many people, including people who voted No in 2014, who would say the only way to guarantee our EU membership is to be independent.” Following the June EU referendum result, Ms. Sturgeon revealed during the SNP’s annual conference in Scotland that she was prepared to introduce draft legislation to hold a second referendum on Scotland’s independence within two years. The results of three polls published by the Financial Times in late July stated that support for Scottish independence had risen from 45 percent to 54 percent since the 23 June EU referendum.

The UK’s nuclear weapons are moved around by road convoys from the Royal Navy’s bases in Scotland to the Atomic Weapons Establishment in southern England.

Should support continue to increase, and should a second referendum on Scottish independence see voters asking for Scotland to leave the UK, this could have serious ramifications for the UK’s nuclear deterrent, and “could make life incredibly difficult for the Westminster government,” Dr. Ritchie adds. It would arguably become politically untenable for the UK to maintain its nuclear weapons facilities at HMNB Clyde and RNAD Coulport as the UK’s nuclear deterrent would based in an independent nation opposed to having nuclear weapons on its soil. This would necessitate the relocation of these facilities into the rump of England, Wales and Northern Ireland. Such a move could create significant local opposition in areas where new facilities to accommodate the UK’s SSBN fleet, and SLBM and warhead storage would be located. Secondly, the construction of new facilities would add significant costs to the Trident renewal programme. In 1994 prices, the upgrade of the facilities at both bases to accommodate the ‘Vanguard’ class, the UGM-133A SLBMs and their warheads cost $2.3 billion, according to a UK Treasury study in 1995. This translates into $3.7 billion in 2015 values. Upgrading existing Royal Navy facilities elsewhere in the UK, can expect to incur similar costs, while constructing new facilities from scratch would almost certainly be more expensive: “Things get very messy politically and financially very expensive it you have to repatriate the nuclear facilities south of the border,” Dr. Ritchie argues.

While Ms. May’s government remains keen to secure the best nuclear deterrent money can buy, costs could continue to dog the progress of the Trident renewal. The British satirical television series Yes Prime Minister once quipped that the original UGM-133A SLBM was “the nuclear missile Harrod’s would sell.” The Trident Renewal has much in common with items stocked in the London luxury store in that it is expensive. Estimates regarding the costs of the renewal have varied. In October 2015, the Reuters news agency argued that it would cost $207 billion to replace the entire Trident weapon system over a 30 year period. Meanwhile, in 2015, the UK’s Strategic Defence and Security Review, which outlines the government’s strategic and defence procurement priorities, stated that the full construction, testing and commissioning of the four ‘Dreadnought’ class SSBNs will be $38.5 billion, with a additional $12.4 billion contingency across a 35 year period.

The UK’s Atomic Weapons Establishment at Aldermaston, west of London, is receiving investments in the form of new testing facilities.

The costs involved are complicated by the so-called ‘Brexit’ vote. The UK economy could contract following the triggering of Article 50, with the possibility of some firms leaving the UK for the European continent so as to remain in the EU’s single market which enables the free movement of goods, services and people within the EU. Added to this is the value of Sterling. Since the 23 June EU referendum the Pound has lost almost 18 percent of its value against the US dollar, which could make components which have to be purchased from the US more expensive if the UK’s currency continues to slide. Furthermore, an independent Scotland would not only see UK nuclear facilities being removed from the country, but also any decision by Scottish voters to support independence could deprive the UK government of the future tax revenues which the Trident renewal will require: According figures for 2013 published by the Scottish government, the country pays around nine percent of all UK income tax. Any decline in such revenues either via independence, or via a post-Article 50 slowdown, could yet hit the Trident renewal. The UK government may have won the vote to renew the Trident weapons system this July, but the potential future constitutional and economic challenges faced by the UK show that the debates regarding the Trident renewal are far from over.

by Thomas Withington