[sandworm101]

>> Royal Navy Nuclear (weapon) submarines are to open a safe with hand-written letters of instruction from the Prime Minister if they can't pick up Radio 4 long-wave

It is one of many factors. Shutting down Radio 4 will not send the subs into attack mode. I do laugh every time I read about the "hand written" part. The assumption is that PMs are unable to use typewriters. Anything typed would therefore have been handled by their secretaries/PAs, making them a target. I have this image in my head of a sub captain not being able to read the PM's handwriting. These are embellished protections generated by novelists.

[arethuza]

I'm pretty sure Peter Hennessy was one of the first to report on the nature of Letters of Last Resort and I'd be inclined to believe his account.

Having them handwritten seems entirely appropriate to me.

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

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

NB Hennessy is obviously well in with the Navy - he has attended during the Perisher course - maybe an advantage to be being a historian who is also a Peer!

[sandworm101]

Be wary of believing any account when it comes to nuclear weapons procedures. There is much misinformation. Changes happen all the time. Some of the public stories have been adopted strait from fiction. The letters have been the subject of so many spy thrillers they are now more myth than functional.

The very concept of the letters presupposes that sub crews have full control over their missiles, that they can fire them based on instructions in a hand-written letter. That does not mesh with the safeguards surrounding other weapons that require external command/codes prior to launch.

[arethuza]

It's also fairly well documented that UK Trident sub warheads do not have Permissive Action Links - the crews of the subs do indeed have the ability to launch without receiving any codes.

The justification for this is pretty simple - timing. In the event of a launch from a likely enemy (the Soviet Union in the bad old days) there simply wasn't enough time to guarantee that a code be transmitted before weapons bursting.

[dragonwriter]

> The very concept of the letters presupposes that sub crews have full control over their missiles, that they can fire them based on instructions in a hand-written letter. That does not mesh with the safeguards surrounding other weapons that require external command/codes prior to launch.

The whole point of the submarine component of the strategic triad is to be the ultimate guarantor of MAD by presenting the capacity for launching a retaliatory strike in the event of sudden destruction of the highest command authorities (and, potentially, the land-based components of the triad), so it is absolutely plausible that submarines have a looser set of controls than bombers and land-based missiles because otherwise there would be no point in having them.

[arethuza]

And in the case of the UK we don't have a triad - just the 4 Vanguard-class boats.