WE177 from Sea King!
Several decades ago some RN chaps were explaining to a sceptical RAF type (me) how their helicopter was nuclear capable. Imagine my surprise when a trip to Hack Green secret nuclear bunker (well recommended if you're in the Crewe area) reveals this wasn't just dark-blue bar talk.
How did this work in practice and was there any chance of survival for those lucky enough to have been selected for such a mission?