Brilliant series. Loved every minute of it. Funny, thought provoking, at times hilarious. Great characters.
My two cents: We are led to believe initially that the 1973 life is a lucid coma dream, occurring in the subconscious of Sam Tyler who is alive in 2006 and suffers a serious traumatic brain injury.
However, for me, as the show goes on, the detail, vividness, strong sense of reality of the "dream" made me wonder if Sam had entered a temporary afterlife or some sort of limbo land. A land hovering between life and death. Sam is going back and forth between life and death. Going back and forth between his old life in 2006 and his new life in 1973.
I saw the Maya leaving him issue as a point in favor of 1973 being reality. It is harsh, but a reality that a person would have to move on and leave a long time coma patient. Not many people could stop their life indefinitely for someone who is no longer among the active living. This would not come from Sam's subconscious or his dream, it comes from reality.
The final scene gives us the answer. After coming to full consciousness in 2006, recovered from his injury, Sam decides he cannot abide his life in 2006. He longs for his 1973 life and therefore commits suicide. He returns then to his new life in 1973. This is confirmation that 1973 had been the after life, the other side. Karma, reincarnation, etc.
Frank Morgan is like the Wizard of Oz. Both were dual characters, played the same two roles. One role was mundane, the other of puppet master. I will have to think more about the meaning of Gene Hunt....
I started watching Ashes to Ashes, but the first scene was so hokey, I stopped. Let me know what you think of it.