The core cast—John Nettles as DCI Tom Barnaby, Jane Wymark as Joyce Barnaby, Daniel Casey as DS Gavin Troy, and Laura Howard in a supporting role—is entirely white British actors in conventional family and professional dynamics fitting the rural English setting. Episode plots, such as Garden of Death (family feuds and poisonings), Dark Autumn (rural community dramas), and others, revolve around classic whodunit elements like village secrets, inheritance disputes, and personal vendettas without any exploration of identity politics, systemic critiques, DEI messaging, or social justice themes.

There are no race-swaps, gender-swaps, prominent LGBTQ+ representation, or lecture moments; diversity is absent and organic to the fictional all-white Midsomer county, which later drew criticism for lack thereof rather than excess. Creator Brian True-May's later comments defending this homogeneity as preserving 'Englishness' underscore the anti-progressive stance of early production, with no evidence of activist intent. Reception focuses purely on entertainment, plot twists, and charm, with no backlash over wokeness—in fact, modern fans praise early seasons for avoiding forced diversity that plagued later ones.