You are using an out of date browser. It may not display this or other websites correctly. You should upgrade or use an alternative browser.
alternatehistory.com
This should probably be posted elsewhere (mods: please move where appopriate) but this is an interesting 2008 documentary about the command chain for UK nuclear weapon release. It's a good source of detail. The Human Button, by Peter Hennessy
"The Secret State: Preparing For The Worst 1945 - 2010" by Peter Hennessy
Planning Armageddon: Britain, the United States and the Command of Western Nuclear Forces 1945-1964" by Stephen Twigge and Len Scott