Spearhead in Space is really funny because Liz spends her first scenes with the Brigadier so clearly believing she's stuck playing the Scully to this man's Mulder. "Oooookay, so you're a UFO-chasing conspiracy nut who's somehow got government pull" NOPE. The Brigadier is one of the most thoroughly regular people on Earth. He just happens to have discovered that his world gets invaded by aliens sometimes.
(And really, the fact that he responded to that discovery by going through government channels and getting an official Earth-defense organization set up with U.N. backing and oversight tells you a lot.)
"Apologies, Dr. Shaw. I'm assigning YOU to the UFO nut, because my men have already shot him once today, and if I have to deal with him for much longer, I'll do the same."