TV show form the late 70s or early 80s. 20th century castaways are stranded on an Island. The natives are dressed in 18th c. Fashion (I remember cocked hats quite distinctly) and enslaved (or perhaps just obedient vassals) to a tyrannical (or maybe rather awe-inspiring) 'Q'. The said 'Q' plays chess.
Sound like The Lost Islands (Australia, 1976)
There also some extracts at Youtube: Ep 1 - "Captured" (there are links to other episodes).