The friendship between the Doctor and Sarah Jane is one of the most exalted in the history of the show and they are seen as on of the series' great double acts. However, in the Fourth Doctor's first season, the pair were joined by someone else: UNIT doctor Harry Sullivan. In contrast to Sarah Jane's feminist personality, Harry was an old-fashioned sort who liked to protect Sarah, calling her 'old girl', and much to the Doctor's annoyance could be a bit of a clutz. Indeed, one of the most famous phrases to do with the character is the Doctor's declaration that 'Harry Sullivan is an imbecile!'. Despite this, the pair became very fond of the bluff and brave Harry who helped them fight the Daleks, the Cybermen and the Sontarans, amongst others. It was a sad loss for them, then, when Harry decided to stay behind on Earth after an adventure facing the Zygons. As well as the Doctor and Sarah losing a good friend, the show lost one of the most good-natured and endearing companions the series has ever had.
