Rachel Jensen Professor Rachel Jensen was the scientific advisor for Group Captain Ian Gilmore of the Intrusion Countermeasures Group during the Shoreditch Incident in the relevant area of London in November 1963 . Allison Williams served as her assistant . She replaced Gilmore as the head of Counter - Measures in 1964 . Biography . Rachel was Jewish . ( AUDIO : " Threshold " , " " ) During World War II , as a member of the Cambridge Group , she worked with computer pioneer Alan Turing ' s team of codebreakers . In the 1950s , she worked in the British Rocket Group ( BRG ) with " Bernard " . ( PROSE : " Who Killed Kennedy " ) As she was Jewish , Rachel never accepted the presence of Professor Heinrich Schumann in the BRG , given that he was a former Nazi who had worked on Adolf Hitler ' s advanced weapons research programmes and was rumoured to have used human test subjects as part of his experiments . The British government never charged him with war crimes as they sought to make use of his scientific acumen . ( AUDIO : " Threshold " ) Another of her colleagues at Cambridge was Professor Jeffrey Broderick , whom Allison believed still had feelings for her as late as 1964 . Rachel claimed that the idea of a relationship with him made her " skin crawl . " ( AUDIO : " Artificial Intelligence " ) Other than Allison , her students at Cambridge included Anne Travers and Ruth Ingram . ( PROSE : " The Scales of Injustice " ) Her grandfather suffered from dementia . ( AUDIO : " The Forgotten Village " ) In 1962 , she began researching artificial intelligence at the Cavendish Laboratory in Cambridge . ( AUDIO : " Threshold " ) Rachel was none too happy about being required to join Counter - Measures , not appreciating Gilmore ' s having requisitioned her against her will via the Peacetime Emergency Powers Act . She also took issue with his military attitude . When the Seventh Doctor appeared unexpectedly and took charge during the Shoreditch Incident in November 1963 , his superior knowledge left Jensen and Allison as little more than observers and commentators . She did , however , examine the ruined body of an Imperial Dalek . She made a half - joking threat about retiring to raise begonia s after the Shoreditch Incident ( TV : " Remembrance of the Daleks " ) and briefly did this ( PROSE : " Who Killed Kennedy " ) , but within a matter of months she resumed her research into artificial intelligence at Cambridge . She kept in touch with Allison but otherwise was a workaholic . ( AUDIO : " Threshold " ) In November 1963 , she met Sir Toby Kinsella for the first time . She was sent by him to Gideon Vale to investigate him and his work . Here She encountered Ace again . Ace managed to get herself rosterred on to help Rachel , hoping that Rachel could hack the algorithm on a secret door . They managed to get into a vault which contained a lot of nuclear warheads . ( AUDIO : " " ) She once said if she were a genius on the same level as Ken Temple , she would never take any time off work . ( AUDIO : " The Pelage Project " ) Thanks to Allison , she was hired by Counter - Measures once again as a consultant and played a key role in stopping the invasion of an alien , energy - based intelligence that Shumann had brought to Earth . After seeing how Counter - Measures barely understood such threats and was not properly funded or equipped , Rachel accepted Sir Toby ' s offer to join the organisation permanently — on the condition that she was supplied with the facilities to continue her research on site and that she would replace Gilmore as its leader . However , she assured him that she would defer to his judgement in all matters of security . ( AUDIO : " Threshold " ) While Gilmore was initially bitter that Rachel had replaced him , he eventually came to respect her not only as a scientist but as his superior officer as well . ( AUDIO : " Artificial Intelligence " ) Her Ministry of Defence contract stated that all of her past , present and future research is the intellectual property of the British government . This allowed Professor Broderick to make use of her theories in creating the artificially intelligent Sentient Engine Generator 2 computer ( Sen - Gen ) . Much to Rachel ' s annoyance , Broderick also programmed Sen - Gen with her voice . After Sen - Gen had tapped into her mind and amplified her subconscious fears , she left a dictation machine into Sir Toby ' s office in Whitehall which featured a recording of herself tearing up her MoD contract and telling him that she thought that he was scheming and manipulative . She sent a copy of the tape to " The Times " . However , the Royal Mail train was intercepted by the MoD and the package was recovered . Sir Toby told Rachel that , had the package been delivered , contingency plans were in place and that the MoD would have claimed that the recording had been faked . ( AUDIO : " Artificial Intelligence " ) Soon after the 1964 general election , Jensen had corrected Shumann ' s notes and was able to build a working teleporter . Her notes were used by General Peters to stage an alien invasion as part of a coup — Jensen swiftly realised that a coup was being orchestrated and , with Gilmore , was able to prevent it . She also ensured that the aliens brought from the teleporter would home in on Peters , killing him . ( AUDIO : " State of Emergency " ) She was concerned about Allison after she killed her fiance . ( AUDIO : " Manhunt " ) In 1965 , Rachel and Gilmore had dinner together but she claimed that it was " perfectly professional . " ( AUDIO : " The Fifth Citadel " ) Her ICMG codename was " Barn Owl " . ( AUDIO : " The Forgotten Village " ) By 1971 , she was acquainted with Professor Bernard Trainor , and had spoken to him about the Doctor , who noted that she spoke very highly of him . However , the Third Doctor expressed ignorance of her when he first met Trainor as his first meeting with her had not yet happened in his personal timeline . ( PROSE : " The Devil Goblins from Neptune " ) Rachel never took sugar in either coffee or tea . ( AUDIO : " Sins of the Fathers " ) She was brainwashed by Templeton to think that he was Toby and another Captain was Gilmore . ( AUDIO : " New Horizons " ) This came from an implant in her neck . ( AUDIO : " The Keep " ) Her autobiography , " The Electrical Dreamer " , made no mention of the Shoreditch Incident at all . ( PROSE : " Remembrance of the Daleks " , " Who Killed Kennedy " ) She was eventually appointed chief scientific adviser to the Cabinet . She served in that position until 1981 , at which time she was succeeded by her former student Anne Travers . ( PROSE : " Millennial Rites " )