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Comment by arethuza | Hacker News Reader

"the UK phsyically cannot fire it without US approval"

I've never seen any evidence supporting that view - we certainly couldn't maintain it for very long without US help but the whole idea of the UK deterrence fleet at the moment is that they have no dependencies on anyone to carry out a launch - for the obvious reason that in most attack scenarios there wouldn't be anyone in the UK left to contact.

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I agree. The Permissive Action Link(PAL), a remote security device for nuclear weapons, was typically used when the state is non-nuclear, yet is a member of NATO. They are secured and deployed by USAF members. But the UK is not one of these states. In fact, you can find evidence that they do not use the PAL on their own weapons, so most likely they do not have them deployed on any of the NATO nuclear weapons stationed in the UK.

https://en.wikipedia.org/wiki/Nuclear_weapons_and_the_United...

"The UK Trident system is highly dependent, and for some purposes completely dependent, on the larger US system."

http://www.publications.parliament.uk/pa/cm200506/cmselect/c...

I don't see anything in that says that a UK sub needs US input to launch - in the worst case they don't need any input to launch (they don't have PALs).

Of course, there are dependencies on US systems for lots of things and if the US withdrew support for our Tridents systems we probably couldn't operate them for very long (months - probably, years probably not).

Is it completely "independent" - of course not - it's a US system and there are very few scenarios where the US and UK wouldn't co-ordinate an attack. But does the UK need "permission" to launch - not as far as I know.

The US can withhold targeting data prior to launch, or switch off guidance after launch.

That is all stated as fact in the Parliamentary report. Not sure which part you disagree with.

Sure, you might be able to sneak a launch and hope they don't detect it, but that's a little farcical for a £100bn defence programme I would've thought.

That's appears to be evidence given to a select committee - so it's one person's view.

AFAIK subs don't use GPS underwater - and missile subs spend most of their missions underwater. The missiles themselves use inertial (hence the dependency of knowing the launch point) and star-sighting:

"GPS has been used on some test flights but is assumed not to be available for a real mission."

https://en.wikipedia.org/wiki/Trident_%28missile%29

I'd be very surprised if the sub don't go to see with at least some target data - kinds of defeats the purpose of the entire system which is set up to give UK Trident sub commanders a surprising amount of leeway:

https://en.wikipedia.org/wiki/Letters_of_last_resort

[Edit: For the record - I am rather passionately anti-Trident and would strongly prefer the UK didn't have them].

"The Future of the British bomb", John Ainslie

http://www.swordofdamocles.org/pdf/future.pdf

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