Fairly Secret Army is a British sitcom which ran to thirteen episodes over two series between 1984 and 1986.

Though not a direct spin-off from The Fall and Rise of Reginald Perrin, the lead character, Major Harry Truscott, was very similar to Geoffrey Palmer's character of Jimmy Anderson from that series, who himself featured in a scene where he tried to recruit Reggie to a secret army with very similar aims to Truscott's (a scene repeated, near verbatim, in episode 2 of Fairly Secret Army).

Harry Kitchener Wellington Truscott (ex Queen's Own West Mercian Lowlanders) is an inept and slightly barmy ex-army man intent on training a group of highly unlikely people into a secret paramilitary organisation.

This idea first emerged in an episode of Perrin when Jimmy confided the plan to Reggie (who rubbished it) and was based on persistent rumours in the 1970s press that several generals were secretly planning a coup to "rescue" Britain from trade union militancy.

[1] Nobbs only started work on the show when he turned down an offer to write a spin-off sitcom for Manuel of Fawlty Towers.