Parker (The Ambassadors of Death)

Private Parker was a UNIT soldier who served under Brigadier Lethbridge-Stewart. Reegan knocked him out to gain access to Space Control's fuel bay and sabotage the Third Doctor's flight. (TV: The Ambassadors of Death)

Behind the scenes
Parker's name is never given in on-screen dialogue; his name is only given in the closing credits. He is also left unnamed in the novelisation.