Fenner

Fenner was a crewmember of the methane refinery on Delta III.

Biography
After a ship landed on Delta III, Fenner and his superior, Thawn, went to to seek out the craft. They came across the TARDIS and mistook the Fourth Doctor for a gun runner, Rohm-Dutt. They took him as a prisoner. Fenner and Thawn returned to the refinery with the Doctor. While they were distracted by their machinery, the Doctor escaped.

Fenner thought the Swampies might as well be slaves, caring little for their livelihood. This affected his treatment of Mensch, who was indeed a slave. Neither Fenner not Thawn considered the Swampies to be people. Nevertheless, when Thawn murdered Dugeen and tried to destroy both Kroll and the Swampies, Fenner was not willing to go along with Thawn until he threatened to kill him too. (DW: The Power of Kroll)

Behind the scenes

 * Philip Madoc, a Doctor Who regular, was called in to play Fenner at the last minute. However, he had misunderstood John Nathan-Turner and thought he was playing the more substantial part of Thawn.