Bret Vyon Bret Vyon was a Space Security Agent who assisted the First Doctor in his quest to stop the Dalek s from conquering the Solar System in 4000 . Biography . Bret was born in Mars Colony 16 in the late 40th century . In 3990 , he joined the Space Security Service , made First Rank in 3995 and Second Rank in 3998 . His sister , Sara Kingdom , also joined the Service . ( TV : " The Daleks ' Master Plan " ) Bret outranked Sara . ( AUDIO : " The Guardian of the Solar System " ) In 3999 at the Great Clock , Bret met an older version of Sara who was travelling with the First Doctor and Steven Taylor . She hugged him and started crying when they met , knowing what would happen to him in a few months . ( AUDIO : " The Guardian of the Solar System " ) He was posted on a mission to the planet Kembel in 4000 with another agent , Kert Gantry , to investigate the disappearance of fellow agent Marc Cory . Gantry was injured and he forced Bret to leave him so he could have a better chance to escape . Almost suffering a similar fate to Marc Cory , Bret was saved when he witnessed the arrival of the First Doctor ' s TARDIS . He waited in the bushes until the Doctor exited to find help for an injured Steven Taylor . Bret then held the Doctor at gunpoint and forced the Doctor to give him the TARDIS key , allowing him to enter the TARDIS . He tried to force Katarina to take him off Kembel , but Steven knocked Bret out . The Doctor returned and placed Bret in a restraining chair and went outside again . Bret managed to convince Katarina that he would not harm her , and gave her two tablets which he said would help cure Steven ' s blood poisoning . When the tablets worked , Katarina let Bret out of the chair , and he took both of them into the jungle when he saw the Dalek s on the TARDIS scanner . He investigated the jungle and saw the Daleks using their flame - throwers to burn down the jungle , after which he returned and warned the Doctor of the danger . The Doctor decided to go to the Daleks ' city to find out their plans . When they entered the city , Bret knocked out Zephon and tied him up . The Doctor donned Zephon ' s cloak and infiltrated the seventh meeting of the Galactic Council . Bret , Steven and Katarina hijacked the " Spar " , Mavic Chen ' s spacecraft . When Zephon sounded the alarm , Bret prepared to take off without the Doctor , but the Doctor managed to get aboard with the stolen taranium core just before they took off . Bret decided to head to Earth to warn them of the Daleks ' plans . The Doctor showed him the tape - recording of Cory ' s SOS message which he had discovered in the jungle . From the Doctor , Bret learned that Chen had allied himself with the Daleks . The Daleks used a remote control deice to force the " Spar " to land on the prison planet Desperus . Bret and Steven managed to fix the damaged controls and managed to take off , but one of the convicts , Kirksen , had managed to get onboard and held Katarina captive in the airlock . When Kirksen forced them to turn back to Kembel , Katarina opened the airlock , killing herself and the convict . Bret managed to land the " Spar " on Earth and took the Doctor and Steven to a research station run by his friend Daxtar . However , Daxtar gave himself away as a traitor when he mentioned the taranium , which he could not have known about unless he was told by Chen . Angry at Daxtar ' s betrayal , Bret shot and killed him . Bret proposed that he could infiltrate the security service and alert the authorities himself . While they were preparing to leave , Bret ' s sister Sara entered . Sara , who had been convinced by Chen that Bret , the Doctor and Steven were traitors , held them all at gunpoint . However , Bret managed to cause enough of a distraction to allow the Doctor and Steven to escape , but was then shot and killed by Sara . Once Sara learned the truth , she allied herself with the Doctor to save Earth and avenge Bret ' s death . ( TV : " The Daleks ' Master Plan " ) Legacy . On the Space Security Service Station 7 , the Eleventh Doctor told Tranter that he had worked with Bret Vyon and Sara Kingdom , prompting the station commander to comment that he had impressive credentials and must have started fighting the Daleks at a very young age . ( COMIC : " The Only Good Dalek " )