In which 1973 serial did Sarah Jane Smith first appear?

Sarah Jane Smith first appeared in the 1973 serial “The Time Warrior.”

“The Time Warrior” is the first serial of Doctor Who’s eleventh season, beginning its four-part broadcast on 15 December 1973. Elisabeth Sladen plays Sarah Jane, an investigative journalist who infiltrates a research facility by posing as her aunt, the virologist Lavinia Smith.

The story sends Sarah Jane into a conflict involving the Third Doctor, a stranded Sontaran commander and medieval England. It introduced Sarah Jane as an independent, determined character rather than simply a passenger waiting to be rescued. She then travelled with the Doctor through the remainder of Jon Pertwee’s era and into the early Fourth Doctor stories.

The serial is notable for more than Sarah Jane’s debut. It also introduced the Sontarans and was the first televised Doctor Who story to name the Doctor’s home planet, Gallifrey. “Planet of the Spiders” is associated with the Third Doctor’s regeneration, while “The Green Death” and “The Sea Devils” feature Sarah Jane later or other companions, not her first appearance.