"Post Horn Gallop" was a very amusing play, set in a crumbling stately home belonging to an impoverished aristocratic family.

Lord Elrood is an eccentric, trigger-happy individual who believes his castle to be under siege from unknown attackers, such as the postman and the butcher's boy, and lurks in corners with his shotgun at the ready. Due to lack of funds, his long suffering wife has been forced to open the castle to the general public for the very first time.

Her nerve-shattered son-in-law, Chester Dreadnought, who arrives for what he hopes will a quiet week-end, ends up being pursued by his two arch enemies, Capone and Wedgewood, as well as by the dotty lovestruck servant Ada, around the secret panels and hidden doors. Meanwhile the cockneys Maggie and Bert, who have come in for two-and-six, are suitable awestruck at the goings-on of the country-house set.