Thomas Brewster Thomas Brewster ( born 1846 or 1847 ) was an orphan , mudlark and street urchin in Victoria n London . He became a companion of the Doctor in his fifth and sixth incarnations . Biography . Meeting the Doctor . Thomas met the Fifth Doctor and Nyssa on 14 November 1867 while he was being haunted by what he thought was the ghost of his mother , who had died in 1851 . After the Doctor helped him , he stowed away in the Doctor ' s TARDIS and accidentally set it on a solo flight . ( AUDIO : " The Haunting of Thomas Brewster " ) Solo travels . Brewster gained limited control over the TARDIS . On one of his stops , the TARDIS was taken from him for ransom and he was forced to work for the Doctor ' s old enemy , Gerry Lenz . At this time , Brewster met the Doctor ' s old friends , Brigadier Lethbridge - Stewart and Polly Wright . The three of them rescued the TARDIS from Lenz and saved the Earth from dying and from a Coffinloader , a beast which fed on dying worlds . ( AUDIO : " The Three Companions " ) Eventually , the TARDIS began to malfunction due to Brewster ' s meddling . Before the ship could come to any further harm , Thomas was helped by an elderly Adric , who got him back to London a few months after his departure . The Doctor invited him to join him on his travels ( AUDIO : " The Boy That Time Forgot " ) but soon after he joined , they returned to the location of one of his previous travels , where it was revealed that Brewster had sold several vital components of the TARDIS to the marooned crew of the " Gamma " . Among the components Brewster sold was the TARDIS ' conceptual geometer , the removal of which greatly destabilised the structure of the TARDIS and eventually caused the collapse of the ship ' s internal dimensions . However , the Doctor was able to reconnect the geometer to the TARDIS , restoring its interior to normal . ( AUDIO : " Time Reef " ) Leaving the Doctor . After they left , Brewster convinced the Doctor to take him to 2008 supposedly to see his future . In fact , he wished to be reunited with a young woman named Connie Winter , whom he had met whilst travelling in the Doctor ' s TARDIS alone . Thomas decided to stay in 2008 with Connie rather than continue travelling with the Doctor and Nyssa . ( AUDIO : " A Perfect World " ) Reunion with the Doctor . Brewster enjoyed his life with Connie , but tragedy struck . She was hit by a car and suffered an irreversible coma . Alone in a time when he didn ' t fit , Brewster found the time machine he had built while under the control of the alien pretending to be his mother in 1867 . He was trying to return to his own time when he was contacted by Symbios , a sentient planet which was being invaded by an alien robot species called the Terravore . Brewster provided Symbios with hosts who were riding the tube . After defeating the Terravores with the Doctor , now in his sixth incarnation , Evelyn Smythe and DI Patricia Menzies , Brewster stole the TARDIS key , snuck aboard and held the Doctor and Evelyn at gunpoint , demanding they return him to his own time . ( AUDIO : " The Crimes of Thomas Brewster " ) Brewster helped the Doctor defeat the Axons . ( AUDIO : " The Feast of Axos " ) After an adventure in Victorian Lancashire , Brewster was left behind by the Doctor . However , he went on to travel with an alien trader . ( AUDIO : " Industrial Evolution " )