Whether it's on or off-screen, some Doctor Who companions' best stories happen after they decide to depart the TARDIS and say goodbye to their Doctor.

Elizabeth Sladen made Sarah Jane Smith the quintessential Doctor Who companion and her appearances reflected the series' evolution.

John Barrowman first appeared as Jack Harkness during Christopher Eccleston's short ... time companion and brought cultural issues to Doctor Who storylines from 2007. Even a robot dog had been ...