Casting features a diverse ensemble including Black, South Asian, and Asian actors in roles like Home Secretary Isaac Turner (Paapa Essiedu, established from prior seasons), journalist Khadija Khan (Indira Varma), and DI Nadia Latif (Ginny Holder), but these appear organic to a modern British intelligence setting without clashing with source material, race/gender-swapping of legacy characters, or forced DEI quotas. No prominent LGBTQ+ representation, gender fluidity, or critiques of patriarchy/masculinity drive the narrative.

A single subplot in Episode 3 portrays far-right activist James Whitlock as an extremist for filing FOI requests on migrant statistics, calling boat arrivals a 'land invasion,' and aiming a sniper at migrants including a child, sparking backlash accusing the show of pro-migrant propaganda and demonizing legitimate concerns. This incidental element introduces modern political framing but does not form the premise, character arcs, or emotional core, which remain thriller-driven.

Creator Ben Chanan cites reflecting news headlines like immigration without stated activist intent. While audience reactions on X highlight 'propaganda' and calls to defund BBC, positive critic reception praises twists and entertainment value, confirming progressive touches are peripheral and do not compromise the traditional storytelling.