28 April 2019

nuclear security

Keys to Armageddon

  • Britain is planning to spend about £40 billion, excluding running costs, to renew its submarine-based independent nuclear deterrent
  • Credible deterrence requires an adversary to believe that nuclear weapons might actually be used against him in a worst case scenario
  • But as a submarine commander in the Cold War, Rob Forsyth learned that the final decision on whether to launch missiles could be more complicated than it appears

By Rob Forsyth

“You have my permission to fire.”

With this simple phrase, 16 nuclear-armed Polaris missiles, each of which was 30 times as powerful as the Hiroshima bomb, could have been launched into the stratosphere on a free-fall path to targets in the former Soviet Union. Their use would have marked the end of the world as we know it; an act of retaliation for the launch of similar nuclear weapons by the Soviet Union at Britain or her Nato partners under the policy of mutually assured destruction. It would have caused a nuclear winter akin to the one that wiped the dinosaurs off the planet. It would have been an act too dreadful for any reasonable person to contemplate for long.

Except that we did. As executive officer of a Polaris submarine in the mid-1970s, I took part in multiple exercises intended to prepare us to launch our missiles in a nuclear confrontation. In the event of a real one I would have been party to authenticating that the order to fire came from the prime minister. I would have been required to stand next to the captain as he inserted his dedicated key in the firing panel and turned it to complete the electronic circuits that would then irrevocably count down to the launch of the first missile. It would have been an unimaginable moment.

It is a matter of history that this never happened for real during the cold war. It is a matter of policy, however, that it still could – for the UK, the US and at least four other countries that maintain a submarine-based nuclear deterrent.

Britain's Polaris submarine HMS Revenge is launched into the River Mersey

The Weapons System Readiness Tests that arrived at any time of the day or night required us to be in a position to launch within 15 minutes. The mere memory of them still sets the blood pounding. Even more realistic was the launch of a fully functioning missile with a dummy warhead 2,500 miles down the Cape Canaveral range off the Florida coast. The thrust of the missile’s launch would cause the submarine to bounce down and up before the compensating system regained control and once again we were stationary on launch depth. Stretch the imagination to a continuous salvo of 16 missiles and sombre thoughts cross one’s mind.

The Cold War was at its height. Nato feared that Soviet tanks could roll across the Warsaw Pact’s western border at any time. Soviet aircraft constantly penetrated our airspace and their submarines seemed to be everywhere. Tension was constantly high. Incidents when the two sides’ huge military machines made contact were frequent – several cases of submarines colliding with euphemistic “icebergs” are on record. In my own case, while temporarily in command because my captain was ill, an intelligence-gathering Soviet trawler seemed determined to intercept us and prevent us from diving as we headed out to our patrol area on the surface. We could not out-run it so I decided to do a crash dive to avoid a collision. I can still hear the noise of its propeller blades passing overhead.

The only justification for the threatened use of the “Doomsday Machine”, as the former US nuclear planner Daniel Ellsberg called it, was that it would deter any sensible enemy from instigating a nuclear exchange. In a sense this view shared common ground with the Campaign for Nuclear Disarmament, whose peace camp was immediately outside the gates of the Faslane Naval Base where Britain’s strategic nuclear submarines are still based. We agreed on the aim of not using nuclear weapons; we just set about achieving it in different ways.

My captain and I had our own private and very serious discussions before we went on patrol together for the first time. We both wanted to be quite clear that we were of the same mind about how we would respond if we received an order to fire. We agreed that we could not obey an unlawful order just because it came with the authority of the prime minister.

The control room of HMS Vigilant, a Trident nuclear submarine, 2016

This view was based on recent history. The Nuremberg Principles established after the Second World War that “the fact that a person acted pursuant to order of his Government or of a superior does not relieve him from responsibility under international law, provided a moral choice was in fact possible to him”. Our dilemma was that the use of nuclear weapons by any yardstick had to be an offence against prevailing humanitarian law as expressed in the Geneva Conventions. In that respect CND were right. Nuclear weapons were (and still are) indiscriminate as to who and what they destroy, and their effects can last for generations. Hiroshima would be a small bonfire compared to what our 16 missiles could do: take out Moscow’s military targets and you would take out Moscow with them.

The question, then, was what would constitute a lawful order to fire. The Soviets’ apparent willingness to use nuclear weapons seemed to pose an existential threat to the West. How much of what they said was bluster and how much was real military intent no one could tell, but given that their avowed policy was to spread Communism worldwide by any means – including military force – we were inclined to believe them. This belief was constantly reinforced by the government, by naval intelligence briefings and by our western media. Soviet media did not hold back either. In any case, my captain and I agreed that, if the UK or Nato was subjected to a nuclear attack, then the norms of humanitarian law no longer applied and we would fire as ordered. In these terrible circumstances the hope, possibly vain, would be to halt further nuclear exchanges.

The US nuclear submarine Henry M Jackson on the Pacific Ocean

What we were not prepared to do under any circumstance was automatically obey an order to fire first with the intention of destroying Soviet targets before they fired at us. This would almost certainly have been unlawful (and arguably still would be) and neither of us had any wish to start a nuclear war based on incorrect intelligence of Soviet intentions. Our unofficial safeguard was to be the BBC. On patrol we were able to receive its radio programmes 24 hours a day. If there had been no warning of escalating hostilities over the airwaves, and if all channels were broadcasting normally when an apparently authentic order to fire arrived, then we were absolutely agreed that we would pause for thought beyond the 15 minutes, not turn the Captain’s Key and break radio silence to phone home. It seems that this has more formally become part of the process by which a Trident submarine commanding officer determines if the British government is still functioning. If he believes it is not, the next step is to open the “letter of last resort” (see box below) stored in his safe. Only then will he know if he should turn the key and say: “You have my permission to fire.”

Commander Robert Forsyth joined the Royal Navy in 1957 and the submarine service in 1961. He commanded conventional and nuclear-powered submarines, was executive officer of a Polaris Missile firing submarine and commanding officer of the Commanding Officer’s Qualifying Course.

Letters of last resort

These are hand-written by each incoming prime minister to each Trident captain, to be opened only if the commanding officer has no communication with Naval Command and believes the UK has suffered a nuclear strike. No one except the prime minister knows what the letters say, and no prime minister has ever revealed their contents after leaving office. However, it has been speculated that the options might include: place yourself under US Command, fire a retaliatory strike or use your own judgment. A fourth option would be: do not retaliate, but whether a prime minister would ever choose it we may never know.

Further reading

  • More about the cold war experiences of Robert Forsyth and some of his contemporaries can be read in Hunter Killers by Iain Ballantyne
  • The Silent Deep by James Jinks and Peter Hennessy is a comprehensive history of the Royal Navy Submarine Service since 1945