Although "Fairly Secret Army" never got much attention, it was a delightful little series starring Geoffrey Palmer, with a challenging premise for a teleplay-writer in these modern times: Make an obscure, far-right, wonderfully stuffy retired British army major into a lovable, and even sympathetic and huggable, fellow. He tries to form a tiny army dedicated to something or other. It's never clear what. Certainly not the overthrow of the British government -- that's the very thing they oppose.
The series, which only ran to about a dozen episodes, was a spin off from the much better-known "Fall and Rise of Reginald Perrin," in which Palmer played Reggie's wonderfully stuffy and perpetually unprepared Army officer brother-in-law, Jimmy (Major James Gordonstoun Anderson). ("Would you have any food, Reggie? Been rather a cockup on the catering front.") Palmer's Major Harry Kitchener Wellington Truscott different name but obviously an extension of the same character -- tries to raise a small and fairly secret army, but has to settle for one adoring upper-class lady, a popinjay sergeant and his wife, and a half-witted corporal (Richard Ridings).
The secret army is soon recruited by a shadowy man from government to infiltrate a revolutionary cell that seems to be as lethal as it is secretive. Good stuff.