Before my time but my dad was a navigator on Vulcans in the 60's, apparently his crew did the longest on nuclear deterrent of any crew, scary times I understand.
He told me that they had been briefed on their targets for if it ever came to it, but there wouldn't be sufficient fuel to get from the drop zone to the landing point if they did go so basically it would have been a one way trip, nobody ever discussed but it as navigator he knew what they needed but they didn't have it. Basically the attitude seemed to be if you were responsible for dropping the bomb you wouldn't want to be around to live with the knowledge of how ever many thousands had been wiped out as a result. He, my mother and sisters, lived off base and at one point he had to have a hand gun there in case they were scrambled and he met opposition from protesters while trying to get into the base.
He's only spoken about it a couple of times and wasn't sensationalising it, he was talking about how frightening that time was and how much more prepared they were to go to war than the public at large realised.
None the less he is very proud of their time on Vulcans, its an aircraft which holds a special place in his heart.