It’s a common myth that the United States has control over the UK’s Trident missile system, that is not the case. Here’s proof.
The Trident missile system is housed on the UK’s four Vanguard class submarines which form the UK’s strategic nuclear deterrent force. Each of the four boats are armed with up to 16 Trident II D5 SLBMs, carrying up to 8 warheads each.
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.
The argument is often 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 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.
In summary, the UK retains full operational control, to the extent that the US could not stop a launch.
A Freedom of Information request proving that the United Kingdom has full operational control over its Trident missile system is displayed below. It can be downloaded here.