No, I think the poster is mis-remembering things which were based on facts.
Donald Michie did work (with Turing!) at Bletchley Park, and he did die in a motor vehicle accident. He was 83 when he died (not 91)[1]. His ex-wife[2] (they had remained friends) was in the car with him and also died. She had never defected to Russia, but she was (or had been) a member of the communist party[2].