Andrea Yates Andrea Yates was a school friend of Sarah Jane Smith who was used by the Trickster to remove Sarah from existence and thereby create an alternate reality . Timeline 1 . On 13 July 1964 , Andrea Yates and Sarah Jane Smith were together on a geography field trip with their school . Their teacher Miss Jeffers complained about them because they were fooling around in the coach and did not sit down . Andrea however was annoyed because they were only going to a " stupid old museum " and not to the pier . Meanwhile Sarah Jane started to read " An Unexpurgated History of the Universe " . Andrea told Sarah Jane that the book was uninteresting but that she wished that she was as clever as Sarah Jane . Andrea was only good at art but Sarah Jane got top marks in every class . When Sarah Jane told Andrea that she was so good because she was reading such books as " An Unexpurgated History of the Universe " , Andrea told her this price was too high for good marks . Then Miss Jeffers gave a handout to the class . They should answer all of the questions on the handout within the next three hours . When their classmates went into the museum Sarah Jane and Andrea sneaked off and went to Westport . They went to the amusement arcade played several games and won some coins . Then they talked about their future . Andrea wanted to make loads of money , marry Ringo Starr and move to Saint - Tropez or she wanted to live with a handsome fella and a semi in Purley . Sarah Jane wanted to become a journalist and to explore the world . She wanted to see everything there was to see and more . Then Andrea Yates suggested to go to the pier . Sarah Jane was worried because it was shut down for repairs , but Andrea convinced her that it was fun to go there . ( PROSE : " Whatever Happened to Sarah Jane ? " ) Andrea died on 13 July 1964 at the age of thirteen while she and Sarah Jane were visiting the pier . After a brief encounter with a bizarrely dressed girl who claimed to be from the future , at Andrea ' s insistence the two entered an out - of - bounds area . A railing gave way , causing Andrea to fall to her death . Timeline 2 . Just before Andrea fell , the Trickster — travelling through time to find a key moment in history that would allow the random destruction of Earth decades later — offered her a chance to switch places with Sarah Jane . The desperate girl agreed and a new timeline was created in which Sarah Jane died in Andrea ' s place . The Trickster then gave Andrea a Verron puzzle box which made her forget about her deal with him , but she remembered what happened to Sarah Jane . Andrea became an artist and eventually moved into 13 Bannerman Road across the street from Alan Jackson and his daughter , Maria . Indeed , no one else remembered her until Maria , who had been been protected from the Tricker ' s meddling thanks to a second Verron puzzle box given to her by Sarah Jane , remembered Sarah Jane and challenged Andrea . Andrea renewed her agreement with the Trickster , which resulted in Maria being taken out of time . This time Alan had the puzzle box . He remembered his daughter and retrieved her from Limbo . With meteorite K67 threatening to destroy Earth and Sarah Jane the only person able to save the world , Andrea repudiated her earlier agreement . Timeline 3 . With her deal with the Trickster taken back , Andrea apparently returned through time to the point when she originally died , with her and Sarah Jane ' s places switched back . She asked Sarah Jane to remember her , before falling to her death and restoring the original timeline . Sarah Jane admitted that the death of Andrea was a catalyst in how she chose to live her life . ( TV : " Whatever Happened to Sarah Jane ? " )