Liberal Democrat MP Manuela Perteghella posed a written question to the Ministry of Defence, asking about the independence of the UK’s nuclear deterrent and steps to reduce reliance on the United States for testing, maintenance, and missile replacement.
Her question, submitted on November 19, 2024, was as follows:
“To ask the Secretary of State for Defence, what steps he is taking to ensure the independence of the nuclear deterrent; and if he will take steps to reduce reliance on the US for the (a) testing, (b) maintenance, and (c) replacement of missiles.”
Armed Forces Minister Luke Pollard responded:
“The United Kingdom’s nuclear deterrent is completely operationally independent. Only the Prime Minister can authorise the use of our nuclear weapons, even if they are to be employed as part of a NATO response.”
Pollard added:
“We have a close and longstanding relationship with the US on all nuclear issues. One result of this close relationship is that we are able to procure certain non-nuclear components from the US, most notably the Trident II D5 missile, significantly reducing the cost of our nuclear deterrent capability.”
We previously explored this here, one of the most common myths around the system is that the United States has control over the UK’s Trident missile system, that is not the case.
The Trident missile system is housed on the UK’s four Vanguard class submarines which form the UK’s strategic nuclear missile force. Each of the four boats are armed with up to 16 Trident II D5 SLBMs, carrying up to 8 warheads each.
The Royal Navy has operated the UK’s Continuous at Sea Deterrent since 1967 when the first SSBN – or Ship Submersible Ballistic Nuclear – HMS Resolution began patrolling armed with the Polaris missile system.
In 1996 HMS Vanguard, the first submarine armed with the Trident missile system, arrived on the Clyde and took over deterrent patrol duties from the Resolution Class.
The four Vanguard-class submarines form the UK’s strategic nuclear deterrent force.
It’s often said that the UK’s Trident nuclear weapons system is not ‘independent’ or that the UK doesn’t have the ability to use the system without the US agreeing to it, in reality however that is simply not the case.
Who controls Trident?
It’s often said that the UK’s Trident nuclear weapons system is not ‘independent’ or that the UK doesn’t have the ability to use the system without the US agreeing to it, in reality the UK does retain full operational control over the system.
One common argument is that the US can simply ‘turn off’ the GPS system and therefore can stop the UK using Trident, this is also a myth, Trident isn’t guided by satellite.
The missile uses a kind of stellar sighting guidance system and inertial navigation to take a reading from the stars to work out the missile’s position and make any adjustments necessary. They do not require GPS.
One source for the confusion could be the fact that, aside from those currently deployed, the leased missiles are held in a communal pool at the US Strategic Weapons facility at King’s Bay, Georgia, USA where maintenance and in-service support of the missiles is undertaken at periodic intervals.
The missiles are jointly maintained, this is much cheaper than the UK doing it on its own and does not give the United States control over any of the weapons deployed on the submarines.
Does the system require American codes to launch?
American operated Trident missiles are controlled through the US Navy chain of command by the US President. ‘Permissive action link technology’ prevents anyone other than the president or someone he has delegated control to authorising a launch.
In 2007, the UK Government revealed that its nuclear weapons were not equipped with Permissive Action Links. Instead, the UK’s nuclear bombs to be dropped by aircraft were armed by just inserting a key into a simple lock similar to those used to protect bicycles from theft, the UK withdrew all air-launched bombs in 1998. The current UK Trident warheads can also be launched by a submarine commander with the support of his crew without any code being transmitted from the chain of command.
The British missiles are controlled through the Royal Navy chain of command all the way up to the Prime Minister. In reality the Prime Minister would make the launch decision in concert with whatever was left of the British government.
The key point here is that the British deterrent does not have permissive action link control, which means it does not rely on the use of codes to fire the system. The UK’s Trident fleet relies purely on military discipline to prevent a launch.
In summary, the UK retains full operational control, to the extent that the US could not stop the UK from using the system. A Freedom of Information request proving that the United Kingdom has full operational control over its Trident missile system can be downloaded here.
A favourite story concerning our independent nuclear deterrent I heard some years ago centred on the ‘launch codes’. A British journalist on assignment in the U.S. noticed the presence of an American official who followed the then President around carrying what looked like a small suitcase. He discovered this ‘suitcase’ contained a device that would send launch codes to U.S. forces to permit the immediate use of nuclear weapons. On returning to the U.K. this journalist approached the MoD and enquired about the U.K.’s launch codes; how were these sent to our submarines? ‘We don’t have any launch codes’ came the reply. ‘Well, in that case what’s to stop a captain going mad and just launching them himself?’ ‘We don’t have people like that in our navy!’ came the horrified reply. Rumour has it the submarines have to tune into Radio Two ‘to make sure all is well back in Blighty’. When he heard this broadcaster Laurie Taylor commented ‘After that why not just launch them anyway’.
Well it would not be Radio 2 as it is broadcast on medium wave/VHF and unlikely to be received in the mid Atlantic. The BBC World Service broadcast on shortwave however.
Try The Home Service and then Radio 4 and a particular news program.
There used to be a fax machine involved in the play j commands! It isn’t now. I’m not joking.
Try The Home Service and then Radio 4 and a particular news program.
There used to be a fax machine involved in the play j commands! It isn’t now. I’m not joking.
I believe that it was supposed to be listening to Radio 4 because it was on “long wave”. Lack of any contact for a set period would result in listening to the “Today Programme”. Still we will never really know, well I hope not.
I seem to recall that the “nuclear codes” that POTUS controls are for the “land based” launchers, after an exercise in the 70’s/80’s when a drill showed that a larger than expected amount of officers with responsibility failed to authorities the launch, but then again maybe it was from the movie “Wargames” with WPORA playing Tic, Tec, Toe.
Either way, another pointless question from a Liberal Democrat nobody.
Great film that. The machine was Joshua.
The nuclear football.
Always assumed the Radio 2 story was factual and not just hearsay.
The process for authorising UK Trident weapons is well set out in the book The Secret State by Peter Hennessy. Yes listening for the Today programme on Radio 4 is part of the process of checking whether the UK has been wiped out. Once the senior officers on the boat have checked then they would follow the instructions in the letter of last resort from the Prime Minister kept in a safe in the sub. The two senior officers on the boat can fire if they decide to do so. There are no permissive action links in the UK firing chain. No one could stop the crew on the boat from firing if they choose to do so.
But I think this story has missed the main point of the MP’s question. They were really asking about our ability to maintain the whole Trident system. That IS dependent on US support. If the US withdraw that support we have no Trident. Could we replace it with a home grown system? Probably, but it would be an enormous national endeavour and it would take time.
Why is the relevant now? Well perhaps people are worried that the incoming US President might not care too much about a UK nuclear deterrent. After all he is said to have been unaware that the UK even had nuclear weapons when he was last President. Also the Nassau deal that Harold MacMillan signed to gain access to Polaris and later Trident gave the US access to Diego Garcia. Perhaps people are worried that the new US President might not look kindly in the deal with Mauritius?