Parker (The Ambassadors of Death)
From Tardis Wiki, the free Doctor Who reference
Private Parker was a UNIT soldier who served under Brigadier Alistair Gordon Lethbridge-Stewart. He guarded Space Control's fuel bay and demanded Reegan's pass before being knocked out and his unconscious form hidden. (TV: The Ambassadors of Death)
Behind the scenes
Parker's name is never mentioned in dialogue or the novelisation; it is only given in the closing credits.