Millson, is Maria Jackson's father. He is divorced from Maria's mother, Chrissie, and he and Maria are seen moving into Bannerman Road in "Invasion of the Bane". He works in IT, blocking super-viruses; he once did an IT job in a school, and is capable, in The Lost Boy, of obtaining an 'Armageddon Virus' that completely wipes out Mr Smith's databanks. He was one of the 98 per cent of the population that became addicted to Bubble Shock! during the Bane's attempted invasion of Earth. He later made a full recovery. Alan and Chrissie appear to still get on when she visits Maria, however Revenge of the Slitheen indicates there is some tension between them, Maria commenting that they used to argue a lot when they lived together. In the episode Whatever Happened to Sarah Jane? Alan becomes involved in fighting of an alien plot, and thus becomes aware of the existence of extraterrestrial life, Mr Smith and of his daughter's involvement with aliens. He appeared in all stories of the first series, except for Warriors of Kudlak. During the Dalek invasion of Earth in the Doctor Who episodes "The Stolen Earth" and "Journey's End, he was in Cornwall with Maria. In the first story of the second season, The Last Sontaran, Alan is offered a job in America, but is unsure about taking it. At the end of the story he takes the job, and he and Maria leave Bannerman Road. However, the group still call for his computer expertise on occasion; Millson appears as Alan Jackson via webcam in The Mark of the Berserker, when in Sarah Jane's absence, Luke and Rani require him to hack into a UNIT database for critical information. He also subsequently uses UNIT technology to track the location of Clyde Langer and his own skills to get in contact with Sarah Jane. K K-9 Mark IV Sarah Jane Smith's pet robot dog, K-9 Mark IV, voiced by John Leeson, is away for much of the series' run, sealing a black hole created by scientists in Switzerland. In the pilot episode, "Invasion of the Bane", Sarah Jane states that he has been away for a year and a half. His orbit brings him into brief contact with Sarah Jane every so often, as seen in "Invasion of the Bane". He also plays a major role toward the end of the final episode of Series