Prior to her enlistment in UNIT, while a lance corporal, she served as Colonel Lethbridge-Stewart's assistant at the London Regiment offices in Battersea during the clean-up after the London Event. She was promoted to corporal at some point between that and the formation of UNIT, where she became one of the initial members of the Brigadier's personal staff. (PROSE: The Forgotten Son, The Scales of Injustice) Mike Yates often spent evenings with Corporal Bell. (AUDIO: The Screaming Skull)