The letters of last resort are four identically worded handwritten letters from the prime minister of the United Kingdom to the commanding officers of the four British ballistic missile submarines and stored on board of each. [A] They contain orders on what action to take if an enemy nuclear strike has both destroyed the British government and has also killed or otherwise incapacitated both the prime minister and their designated "second person" of responsibility, typically a high-ranking member of the Cabinet such as the deputy prime minister or the first secretary of state. If the orders are carried out, the action taken could be the last official act of His Majesty's Government. [2]
If the letters are not used during the term of the prime minister who wrote them, they are destroyed unopened after that person leaves office, so that their content remains unknown to anyone except the issuer. [3]
A new prime minister writes a set of letters immediately after taking office and being told by the Chief of the Defence Staff "precisely what damage a Trident missile could cause". [4] The documents are then delivered to the submarines in sealed envelopes, and the previous prime minister's letters are destroyed without being opened. [B] [5]
In the event of the deaths of both the prime minister and the designated alternative decision-maker as a result of a nuclear strike, the commander(s) of any nuclear submarine(s) on patrol at the time would use a series of checks to ascertain whether the letters of last resort must be opened. [6]
According to Peter Hennessy's book The Secret State: Whitehall and the Cold War, the process by which a Vanguard-class submarine commander would determine if the British government continues to function includes, amongst other checks, establishing whether BBC Radio 4 continues broadcasting. [7]
In 1983, the procedure for Polaris submarines was to open the envelopes if there was an evident nuclear attack, or if all UK naval broadcasts had ceased for four hours. [8]
While the contents of these letters are secret, according to the December 2008 BBC Radio 4 documentary The Human Button, there were four known options given to the prime minister to include in the letters. The prime minister might instruct the submarine commander to:
The Guardian reported in 2016 that the options are said to include: "Put yourself under the command of the United States, if it is still there", "Go to Australia", "Retaliate", or "Use your own judgement". [4] The actual option chosen remains known only to the writer of the letter.
David Greig's 2012 play The Letter of Last Resort deals with the consequences and paradoxes of the letters. [9] The play was first staged in February 2012 as a part of a cycle of plays on "The Bomb" at the Tricycle Theatre in London, directed by Nicolas Kent, with Belinda Lang playing the role of the incoming prime minister and Simon Chandler, her advisor. [10] The production was also seen at the Traverse Theatre in Edinburgh, for the Edinburgh Fringe later the same year. [11] The following year it was broadcast on BBC Radio 4, with the same cast, first transmitted on 1 June 2013. [12]
The KGB's attempts to obtain the contents of the letters of last resort are part of the plot of the BBC Cold War spy drama The Game (2014). [13]
The Ohio class of nuclear-powered submarines includes the United States Navy's 14 ballistic missile submarines (SSBNs) and its four cruise missile submarines (SSGNs). Each displacing 18,750 tons submerged, the Ohio-class boats are the largest submarines ever built for the U.S. Navy. They are also the third-largest submarines ever built, behind the Russian Navy's Soviet era 48,000-ton Typhoon class, the last of which was retired in 2023, and 24,000-ton Borei class. Capable of carrying 24 Trident II missiles apiece, the Ohio class are equipped with just as many missiles as, if not more than, either the Borei class (16) or the deactivated Typhoon class (20).
The Trident missile is a submarine-launched ballistic missile (SLBM) equipped with multiple independently targetable reentry vehicles (MIRV). Originally developed by Lockheed Missiles and Space Corporation, the missile is armed with thermonuclear warheads and is launched from nuclear-powered ballistic missile submarines (SSBNs). Trident missiles are carried by twelve United States Navy Ohio-class submarines, with American warheads, as well as four Royal Navy Vanguard-class submarines, with British warheads. The missile is named after the mythological trident of Neptune.
The Vanguard class is a class of nuclear-powered ballistic missile submarines (SSBNs) in service with the Royal Navy. The class was introduced in 1994 as part of the Trident nuclear programme, and comprises four vessels: Vanguard, Victorious, Vigilant and Vengeance, built between 1986 and 1999 at Barrow-in-Furness by Vickers Shipbuilding and Engineering, now owned by BAE Systems. All four boats are based at HM Naval Base Clyde , 40 km (25 mi) west of Glasgow, Scotland.
Chevaline was a system to improve the penetrability of the warheads used by the British Polaris nuclear weapons system. Devised as an answer to the improved Soviet anti-ballistic missile defences around Moscow, the system increased the probability that at least one warhead would penetrate Moscow's anti-ballistic missile (ABM) defences, something which the Royal Navy's earlier UGM-27 Polaris re-entry vehicles (RVs) were thought to be unlikely to do.
A ballistic missile submarine is a submarine capable of deploying submarine-launched ballistic missiles (SLBMs) with nuclear warheads. These submarines became a major weapon system in the Cold War because of their nuclear deterrence capability. They can fire missiles thousands of kilometers from their targets, and acoustic quieting makes them difficult to detect, thus making them a survivable deterrent in the event of a first strike and a key element of the mutual assured destruction policy of nuclear deterrence. The deployment of ballistic missile submarines is dominated by the United States and Russia. In fact, 70% of nuclear warheads in the USA are carried by SSBN submarines.
The Rolls-Royce pressurised water reactor (PWR) series has powered the Royal Navy's nuclear submarines since the Valiant class, commissioned in 1966.
The United Kingdom possesses, or has possessed, a variety of weapons of mass destruction, including nuclear, biological, and chemical weapons. The United Kingdom is one of the five official nuclear weapon states under the Treaty on the Non-Proliferation of Nuclear Weapons. The UK renounced the use of chemical and biological weapons in 1956 and subsequently destroyed its general stocks.
The UGM-133A Trident II, or Trident D5 is a submarine-launched ballistic missile (SLBM), built by Lockheed Martin Space in Sunnyvale, California, and deployed with the United States and Royal Navy. It was first deployed in March 1990, and remains in service. The Trident II Strategic Weapons System is an improved SLBM with greater accuracy, payload, and range than the earlier Trident C-4. It is a key element of the U.S. strategic nuclear triad and strengthens U.S. strategic deterrence. The Trident II is considered to be a durable sea-based system capable of engaging many targets. It has payload flexibility that can accommodate various treaty requirements, such as New START. The Trident II's increased payload allows nuclear deterrence to be accomplished with fewer submarines, and its high accuracy—approaching that of land-based missiles—enables it to be used as a first strike weapon.
The eleventh HMS Vanguard of the Royal Navy is the lead boat of her class of Trident ballistic missile-armed submarines. The submarine is based at Faslane, HMNB Clyde, Argyll, Scotland.
His Majesty's Naval Base, Clyde, primarily sited at Faslane on the Gare Loch, is one of three operating bases in the United Kingdom for the Royal Navy. It is the navy's headquarters in Scotland and is best known as the home of Britain's nuclear weapons, in the form of nuclear submarines armed with Trident missiles.
In 1952, the United Kingdom became the third country to develop and test nuclear weapons, and is one of the five nuclear-weapon states under the Treaty on the Non-Proliferation of Nuclear Weapons.
HMSVictorious is the second Vanguard-class submarine of the Royal Navy. Victorious carries the Trident ballistic missile, the UK's nuclear deterrent.
HMSVigilant is the third Vanguard-class submarine of the Royal Navy. Vigilant carries the Trident ballistic missile, the United Kingdom's nuclear deterrent.
HMS Vengeance is the fourth and final Vanguard-class submarine of the Royal Navy. Vengeance carries the Trident ballistic missile, the UK's nuclear deterrent.
The Royal Navy Submarine Service is one of the five fighting arms of the Royal Navy. It is sometimes known as the Silent Service, as submarines are generally required to operate undetected.
Royal Naval Armaments Depot Coulport, shortened to RNAD Coulport, on Loch Long in Argyll, Scotland, is the storage and loading facility for the nuclear warheads of the United Kingdom's Trident programme.
The Samson Option is Israel's deterrence strategy of massive retaliation with nuclear weapons as a "last resort" against a country whose military has invaded and/or destroyed much of Israel. Commentators also have employed the term to refer to situations where non-nuclear, non-Israeli actors have threatened conventional weapons retaliation.
The Dreadnought class is the future replacement for the Royal Navy's Vanguard class of ballistic missile submarines. Like their predecessors they will carry Trident II D-5 missiles. The Vanguard submarines entered service in the United Kingdom in the 1990s with an intended service life of 25 years. Their replacement is necessary for maintaining a continuous at-sea deterrent (CASD), the principle of operation behind the Trident system.
Trident, also known as the Trident nuclear programme or Trident nuclear deterrent, covers the development, procurement and operation of nuclear weapons in the United Kingdom and their means of delivery. Its purpose as stated by the Ministry of Defence is to "deter the most extreme threats to our national security and way of life, which cannot be done by other means". Trident is an operational system of four Vanguard-class submarines armed with Trident II D-5 ballistic missiles, able to deliver thermonuclear warheads from multiple independently targetable re-entry vehicles (MIRVs). It is operated by the Royal Navy and based at Clyde Naval Base on the west coast of Scotland. At least one submarine is always on patrol to provide a continuous at-sea capability. The missiles are manufactured in the United States, while the warheads are British.
Dead Hand, also known as Perimeter, is a Cold War–era automatic or semi-automatic nuclear weapons control system that was constructed by the Soviet Union. The system remains in use in the post-Soviet Russian Federation. An example of fail-deadly and mutual assured destruction deterrence, it can initiate the launch of the Russian intercontinental ballistic missiles (ICBMs) by sending a pre-entered highest-authority order from the General Staff of the Armed Forces, Strategic Missile Force Management to command posts and individual silos if a nuclear strike is detected by seismic, light, radioactivity, and pressure sensors even with the commanding elements fully destroyed. By most accounts, it is normally switched off and is supposed to be activated during times of crisis; however, as of 2009, it was said to remain fully functional and able to serve its purpose when needed. Accounts differ on whether the system, once activated by the country's leadership, will launch missiles fully automatic or if there is still a human approval process involved, with newer sources suggesting the latter.
[E]very prime minister in recent years has written such a letter and ... letters that go unused (Tony Blair's for instance) are destroyed without being read.