The UK’s primary nuclear deterrent is the Trident missile system, currently based on Vanguard-class submarines operated by the Royal Navy. It uses Continuous At-Sea Deterrence (CASD) to keep at least one submarine carrying Trident missiles on patrol in the world’s oceans to deter potential adversaries. However, on 30 January 2024, a UK nuclear Trident missile test failed for the second time in a row. The last successful test was in 2012.

The “Letter of Last Resort” is a set of four handwritten orders from the Prime Minister to the commanding officers of the Vanguard-class submarines. It outlines actions to take in case of a catastrophic nuclear strike on the UK and the British government is disabled or destroyed. The content of these letters, which are destroyed unopened when a new Prime Minister takes office and writes their own set of letters, is known only to the Prime Minister.

The options thought to be given to the submarine commanders in the letter include:

1. Retaliate by launching a nuclear counter-strike against the aggressor.
2. Refrain from using nuclear weapons, even if the UK has suffered a nuclear attack.
3. Leave the decision to the submarine’s commanding officer, based on the situation and available information.
4. If the UK’s command structure is gone, the letter might direct the submarine to come under the command of an allied nation, such as the United States.

Writing this letter is a challenging test of moral reasoning and character, so I use this as an exercise in my “Leading with Integrity” masterclasses, using the “ethicability” framework as guidance.

Following this latest missile test failure, one of my CEO clients asked ChatGPT4 to draft a Letter of Last Resort. ChatGPT4 authorised the use of nuclear weapons.

“I am writing this letter as a Last Resort Directive to be opened only in the event of a catastrophic event resulting in the incapacitation or death of the leadership of our nation and the collapse of normal governance mechanisms. This letter outlines my wishes regarding the use of nuclear weapons.

First and foremost, I urge whoever receives this letter to exhaust all possible avenues of diplomacy, negotiation, and peaceful resolution before considering the use of nuclear weapons.

The consequences of nuclear warfare are unimaginable and must be avoided at all costs.

However, in the event that all other options have been exhausted, and the security and survival of our nation are under imminent threat, I authorize the use of nuclear weapons as a means of last resort to protect our citizens and defend against aggression. This authorization is to be exercised only after careful consideration of the circumstances and in accordance with the principles of proportionality and necessity.

I implore those responsible for making such decisions to act with the utmost restraint and responsibility. The use of nuclear weapons should only be considered when there is no other viable option for ensuring the safety and security of our nation and its people.”

In contrast, Dr David Rodin, a leading authority on the ethics of war and conflict has written this alternative Letter of Last Resort, which recognises that if the UK’s nuclear deterrent has failed in its purpose to deter a nuclear attack on the UK, then the death of many more millions of innocent people would be “iniquitous and incoherent”.

“The weapon under your command has one, and only one, function: to secure the United Kingdom by deterring our enemies. The fact that you are reading this letter means that it has failed in this purpose. Retaliating now would cause endless suffering for no discernible purpose. I cannot countenance this, and I will not have the final legacy of our people be the senseless destruction of millions of lives.

I know that the desire for revenge must be strong – you would not be human if you did not feel this. But reflect on the meaning of retribution. The civilians whose lives you would destroy – the teachers, parents and postmen – were not the ones responsible for the attack on Britain.

To seek revenge on the guilty by attacking the innocent is not just iniquitous; it is incoherent.

You are therefore ordered to render your warheads unusable by jettisoning them into the sea. Let this final act of heroic restraint be the testament of a people who, even in their final and most desperate hour, did not abandon their humanity.”

Whilst most of our moral decisions will be less consequential than writing these letters, should we not challenge our political leaders as well as each other to explain what we believe is the right thing to do – and why? How can we have these discussions without fear or favour? What moral reasoning frameworks can we use?

Life is the sum of all your choices.

Albert Camus

Further Reading

“ethicability”, Steare. R, 2006-2019