21-07-2025
British nuclear sub commanders given note on what to do if WW3 breaks out
PM writes four identical letters that are handed to the commander of each of the UK's Vanguard-class submarines
The commanders of the UK's nuclear submarine fleet each hold a handwritten note from the Prime Minister, outlining instructions in the event of the country's leadership being obliterated.
These 'letters of last resort', which are torn up and rewritten with every change of PM, instruct the Trident submarine crew on what to do if the government falls due to a nuclear attack or pandemic.
The UK's nuclear deterrent is solely based on the submarine-launched ballistic missile system deployed across its four Vanguard-class submarines operating on a continuous at-sea deterrent.
Each submarine is equipped with up to 40 deployed Trident D5 warheads, weighing 59,000 kg and capable of delivering multiple devastating 475Kt yields to any target within range of 7,000 miles and can remain submerged for months at a time.
These formidable deterrents, which cost £5.8billion each to build when adjusted for inflation, stretch to 491 feet in length and all contain a chilling, handwritten command from the Prime Minister should a nuclear conflict break out, reports the Express.
The notorious Last Resort Letters are torn up and rewritten each time a new Prime Minister is elected, and their contents are shrouded in mystery.
No official letter has been seen by the public, but their existence has been confirmed by military officials.
The four Vanguard-class submarines: Vanguard, Victorious, Vigilant and Vengeance, carry identical letters containing instructions on what to do if the British government and its successors are wiped out by a nuclear attack.
As reported by BBC Radio 4 and The Guardian in 2016, these letters, penned by the sitting Prime Minister, present a list of options for the submarine's crew of over 130 members.
Reportedly, the options include: "Put yourself under the command of the United States, if it is still there", "Go to Australia", "Retaliate", or "Use your own judgement". However, only the author knows the chosen option.
Historian Peter Hennessy, in his book 'The Secret State: Whitehall and the Cold War', explains that the submarine commanders would determine whether the British government had fallen by conducting checks, including seeing if BBC Radio 4 was still broadcasting.
The Vanguard vessels are due to be replaced within the next ten years by the upgraded Dreadnought fleet, which will also carry the Trident D5 nuclear deterrent.
Construction of these four replacements is currently in progress, with the first expected to be ready in the 'early 2030s' while the current deterrent continues to patrol the world's oceans.
Although the location of the patrolling vessels is classified, HMNB Clyde (Faslane) serves as the primary base for the Vanguard class and is also home to the Royal Navy's submarine service.
Fortunately, up to now, no commanding officer has had to open a Last Resort Letter and long may this continue to be the case.
