Harry Sullivan

Lieutenant Harry Sullivan, a naval surgeon seconded to UNIT. He became one of the Doctor's companions when the Doctor and Sarah lured him into the Tardis. Harry was accident-prone, and while they were in flight, he twisted the helmic regulator , which took them to Space Station Nerva. After encountering several monsters (such as the Daleks, the Sontarans and the Cybermen), the Tardis landed in Scotland, where Harry declined the offer of a trip to London in the Tardis.

Harry Sullivan was in Robot to Terror of the Zygons, plus The Android Invasion: Episode 4 (where he was only an android in episodes 2 and 3).