Jump to content

Letters of last resort

From Wikipedia, the free encyclopedia

A dark grey submarine slightly visible above water.
HMS Vigilant, one of four Vanguard-class submarines comprising the UK's nuclear deterrent.

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.[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:

  1. retaliate with nuclear weapons;
  2. not retaliate;
  3. use their own judgement; or,
  4. place the submarine under an allied country's command, if possible. The documentary mentions Australia and the United States.

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]

See also[edit]


  1. ^ The United Kingdom relies on four Vanguard-class submarines to provide its nuclear deterrent. At least one submarine is always armed and on active service, carrying up to 16 Trident II submarine-launched ballistic missiles. Each missile has a range of 7,000 miles (11,000 km), and can carry 12 independently controlled warheads each capable of destroying a large city.[1]
  2. ^ In the immediate aftermath of a Prime Minister leaving office, letters on board submarines at sea remain valid until they can be exchanged.


  1. ^ "Brown move to cut UK nuclear subs". BBC News. 23 September 2009. Retrieved 24 January 2011.
  2. ^ Taylor, Adam (13 July 2016). "Every new British prime minister pens a handwritten 'letter of last resort' outlining nuclear retaliation". Washington Post. Retrieved 13 July 2016.
  3. ^ Rosenbaum, Ron (January 2009). "The Letter of Last Resort". Slate Magazine. Retrieved 18 March 2012. [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.
  4. ^ a b Norton-Taylor, Richard (11 July 2016). "Theresa May's first job: decide on UK's nuclear response". The Guardian. Retrieved 13 July 2016.
  5. ^ Bunkall, Alistair (13 July 2016). "May To Be Handed Keys To Nuclear Red Button". Sky News. Retrieved 13 July 2016.
  6. ^ "Theresa May's grim first task: Preparing for nuclear armageddon". Politico. 15 July 2016. Retrieved 15 July 2016.
  7. ^ Rogoway, Tyler (1 February 2017). "Letters Of Last Resort Are Post-Apocalyptic Orders for UK Vanguard Sub Crews". The Drive. Retrieved 3 December 2018.
  8. ^ Goodall, David (26 May 1983). "Arrangements for briefing a new Prime Minister in the event of a change of administration following the 1983 General Election" (PDF). TNA) (published 1 August 2013). CAB 196/124. Retrieved 5 September 2013.
  9. ^ Grieg, David (30 September 2015). "Letter of Last Resort". frontstep.co.uk. Archived from the original on 28 May 2017. Retrieved 6 February 2022.
  10. ^ Billington, Michael (21 February 2012). "The Bomb – review". The Guardian. ISSN 0261-3077.
  11. ^ Edinburgh Transfer: The Letter of Last Resort Archived 10 July 2017 at the Wayback Machine, Tricycle Theatre, August 2012
  12. ^ "Saturday Drama, The Last Resort". BBC Radio 4. 1 June 2013. Retrieved 1 June 2013.
  13. ^ Frost, Vicky (7 May 2015). "The Game recap: series one, episode two – Operation Glass is revealed". The Guardian. Retrieved 14 November 2018.

External links[edit]