D is for... Deciders

The three leaders of the Starliner community on the planet of Alzarius. They oversaw the community's efforts to prepare the vessel for its eventual return to the planet Terradon. Decider Draith was killed when he was dragged into the marshes at the time of Mistfall, when the community took refuge in the Starliner from poisonous gases. This event took place every 50 years. The surviving pair of Deciders - Nefred and Garif - offered the vacant position of Third Decider to Login. The Doctor revealed that the vessel had been ready for lift-off for many years, but no-one knew how to launch it.
At Mistfall, savage reptilian creatures emerged from the marshes and were compelled to go to the Starliner. An infected Romana allowed them entry, and Nefred was mortally wounded. He admitted to the others that they could never return to Terradon, as they had never come from there. The community were actually descended from the Marshmen. After the Marshmen had been forced back outside, the Doctor showed Login and Garif how to take off.

Played by: Leonard Maguire (Draith), James Bree (Nefred), Alan Rowe (Garif) and George Baker (Login). Appearances: Full Circle (1980).

• Two of the Deciders had made multiple appearances in Doctor Who. This was the fourth and final appearance for Alan Rowe. He had previously appeared in The Moonbase, The Time Warrior, and Horror of Fang Rock. Bree had previously featured in The War Games, and would later return as the Keeper of the Matrix for the final section of The Trial of a Time Lord.