Barnaby Miller

 was an MI5 agent and a colleague of a scientist creating a wave cancellation frequency modulator in 1964. When the Fourth Doctor and Romana II came to visit the scientist after K9 Mark II malfunctioned in June of that year, he helped the Doctor in his investigations. He worked for the security forces and was concerned when the Doctor wanted to shut down the NATO forces radar and radio systems to stop the Vardans. (AUDIO: Wave of Destruction)