Cedric Chivers
Cedric Chivers was the friend of Susan Foreman in 1963 and one of her classmates at Coal Hill School. In October of that year, he protected her when Mavis attacked her. He had wild ideas about Susan's home. He took her on the London Underground, which she was amazed about. Colonel Rook was his uncle, and Cedric spied on Susan at his request. (AUDIO: Hunters of Earth)
By 2013, he was teaching at Oxford, according to Alice Watson he had simply forgotten to retire. He helped to create a time machine, he knew it worked as he was given himself the instructions from the future. The Eleventh Doctor's influence, by getting him and Susan to by a Bob Dylan record, which led to him to marry a girl he met a a Dylan concert. The memory of his children and grandchildren stopped him from entering the time machine allowing the Doctor to stop the Creevix. (AUDIO: The Time Machine)
