Madeleine Fairweather

 was the mother of Byron and a friend to Charlotte Pollard. She was the only survivor when the SS Britavia went missing. Before the ship went missing she stowed away on board and disguised herself as a part of the crew, just like Charley did on the R101. After the Cybermen attacked the ship she forgot her real identity and took on the alias of Charlotte Pollard. (AUDIO: The Girl Who Never Was)