Letters of last resort

Letters of last resort

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The letters of last resort are four identically-worded, hand written letters written by the Prime Minister of the United Kingdom
Prime Minister of the United Kingdom
The Prime Minister of the United Kingdom of Great Britain and Northern Ireland is the Head of Her Majesty's Government in the United Kingdom. The Prime Minister and Cabinet are collectively accountable for their policies and actions to the Sovereign, to Parliament, to their political party and...

 to the four captains of the four British ballistic missile submarines
Vanguard class submarine
The Vanguard class are the Royal Navy's current nuclear ballistic missile submarines , each armed with up to 16 Trident II Submarine-launched ballistic missiles...

. They contain orders on what action to take in the event that an enemy nuclear strike has destroyed the British state and has killed or incapacitated the Prime Minister and the "second person" (normally a high ranking member of the Cabinet
Cabinet of the United Kingdom
The Cabinet of the United Kingdom is the collective decision-making body of Her Majesty's Government in the United Kingdom, composed of the Prime Minister and some 22 Cabinet Ministers, the most senior of the government ministers....

) whom the Prime Minister has designated to make a decision on how to act in the event of the Prime Minister's death. In the event that the orders were to be carried out, the action taken could be the last act of the British state, and has the capability of figuratively destroying the world.

The letters are stored inside two safes in the control room of each submarine. The letters are destroyed unopened whenever a Prime Minister leaves office, so what action to take is only ever known to previous Prime Ministers. However, all relevant former Prime Ministers have supported an "independent nuclear deterrent", as does incumbent David Cameron
David Cameron
David William Donald Cameron is the current Prime Minister of the United Kingdom, First Lord of the Treasury, Minister for the Civil Service and Leader of the Conservative Party. Cameron represents Witney as its Member of Parliament ....



In the event of the death of the Prime Minister and the designated alternate decision-maker as a result of a nuclear strike, the commander(s) of the nuclear submarine(s) (of which there is always one still active) will use a series of checks to ascertain whether the letters of the last resort will have to be opened. According to Peter Hennessy
Peter Hennessy
Peter John Hennessy, Baron Hennessy of Nympsfield, FBA is an English historian of government. Since 1992, he has been Attlee Professor of Contemporary British History at Queen Mary, University of London.-Early life:...

's book Secret State: Whitehall and the cold war 1945 to 1970, the process by which a Trident submarine would determine if the British government continues to function includes, amongst other checks, establishing whether BBC Radio 4
BBC Radio 4
BBC Radio 4 is a British domestic radio station, operated and owned by the BBC, that broadcasts a wide variety of spoken-word programmes, including news, drama, comedy, science and history. It replaced the BBC Home Service in 1967. The station controller is currently Gwyneth Williams, and the...

 continues broadcasting.


Although the final orders of the Prime Minister are at his or her discretion and no fixed options exist, four known options are often presented to Prime Ministers by military advisers when writing such letters of last resort:
  1. Captain ordered to retaliate to the nuclear attack on the UK with the use of nuclear weapon(s). Retaliation would result in launching the submarine's nuclear weapon(s), most likely against the instigator(s) of the nuclear attack on the UK. Prime minister could also specify if retaliation should be a tit-for-tat response.
  2. Captain ordered not to retaliate to the nuclear attack on the UK with use of nuclear weapons. The prime minister may well consider that the nuclear deterrent has failed and retaliation could result in mutual assured destruction
    Mutual assured destruction
    Mutual Assured Destruction, or mutually assured destruction , is a doctrine of military strategy and national security policy in which a full-scale use of high-yield weapons of mass destruction by two opposing sides would effectively result in the complete, utter and irrevocable annihilation of...

     and nuclear war. Consequently, such retaliation may be considered futile and unwise if the existence of humanity
    Humanity may refer to:* The human species**The total world population* Human nature, psychological characteristics that all normal humans have in common**Compassion**Empathy**Altruism**Aggression**Fear...

     is at risk.
  3. Captain given prerogative to act of his own accord and ordered to take decision based on his judgment. Prime Minister has refused or failed to give a clear order in the letter. Consequently, it is up to the captain to decide what action to take, such as to retaliate or back down.
  4. Captain ordered to place himself and his submarine under the command of an allied nation. The Prime Minister could give responsibility of what action to take to the Prime Minister or President of the designated ally nation(s). One of these designated nations could be one of the monarch
    Monarchy of the United Kingdom
    The monarchy of the United Kingdom is the constitutional monarchy of the United Kingdom and its overseas territories. The present monarch, Queen Elizabeth II, has reigned since 6 February 1952. She and her immediate family undertake various official, ceremonial and representational duties...

    's Commonwealth realms
    Commonwealth Realm
    A Commonwealth realm is a sovereign state within the Commonwealth of Nations that has Elizabeth II as its monarch and head of state. The sixteen current realms have a combined land area of 18.8 million km² , and a population of 134 million, of which all, except about two million, live in the six...

     such as the Government of Australia
    Government of Australia
    The Commonwealth of Australia is a federal constitutional monarchy under a parliamentary democracy. The Commonwealth of Australia was formed in 1901 as a result of an agreement among six self-governing British colonies, which became the six states...

     or Government of Canada
    Government of Canada
    The Government of Canada, formally Her Majesty's Government, is the system whereby the federation of Canada is administered by a common authority; in Canadian English, the term can mean either the collective set of institutions or specifically the Queen-in-Council...

     depending on both the location of the given vessel and current geopolitical issues. Alternatively, the Prime Minister may well give command of what action to take to a fellow nuclear power
    Nuclear power
    Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...

     such as the President of the United States
    President of the United States
    The President of the United States of America is the head of state and head of government of the United States. The president leads the executive branch of the federal government and is the commander-in-chief of the United States Armed Forces....

     or the President of the French Republic
    President of the French Republic
    The President of the French Republic colloquially referred to in English as the President of France, is France's elected Head of State....

     for example. In addition, the Prime Minister may ask the captain to relay commands to allied nations, state what level of authority they will have over the use of his submarine and whether to place the UK's nuclear arsenal
    Nuclear weapons and the United Kingdom
    The United Kingdom was the third country to test an independently developed nuclear weapon, in October 1952. It is one of the five "Nuclear Weapons States" under the Nuclear Non-Proliferation Treaty, which the UK ratified in 1968...

     under the command of an allied nation.

This system of issuing notes containing orders in the event of the head of government's death is said to be unique to the United Kingdom although the concept of written last orders, particularly of a ship's captain, is a naval tradition, with other nuclear powers using different procedures.

Past Prime Ministers

Only one former Prime Minister, James Callaghan
James Callaghan
Leonard James Callaghan, Baron Callaghan of Cardiff, KG, PC , was a British Labour politician, who was Prime Minister of the United Kingdom from 1976 to 1979 and Leader of the Labour Party from 1976 to 1980...

, has publicly given any insight on his orders. Callaghan stated that, although in a situation where nuclear weapon use was required, and thus the whole purpose and value of the weapon as a deterrent had failed, he would have ordered use of nuclear weapons, if needed: If we had got to that point, where it was, I felt it was necessary to do it, then I would have done it (used the weapon). But if I had lived after pressing that button, I could have never forgiven myself.