Davis (Logopolis)

PC Davis was a police officer, who along with an inspector and another policeman, discovered the shrunken corpse of Tegan Jovanka's aunt Vanessa in her car in 1981.

When the three policemen found the Fourth Doctor at the scene of the crime, the inspector accused the Doctor of the death. While taking the Doctor to the police station, Adric caused a diversion, pretending he was injured in a bicycle accident. Davis went over to help, but Adric pushed Davis over and ran, and the Doctor and Adric escaped into the TARDIS. When the inspector and Davis finally opened the TARDIS door, they found it had already dematerialised. (TV: Logopolis)

Behind the scenes
Davis is only named once in the entire episode, by the inspector in part two.