Academic and critical readings highlight the narrative's engagement with UK anxieties over immigration, declining birth rates, demographic shifts, and a fabricated 'Celtic' white community seeking to erase biracial elements for a 'pure' future, positioning traditionalist isolationism as xenophobic and tied to ethnic genocide motifs. Creator Dennis Kelly cited concerns over isolationism and societal division as drivers, aligning the story with critiques of Brexit-era populism and anti-immigrant sentiment rather than neutral thriller tropes.

Summer episodes with Jude Law's Sam add layers of personal racism and blame-shifting onto immigrant partners, while the overall structure uses Helen's race and family as a focal point for the island's rejection of modernity and outsiders. This goes beyond incidental diversity or organic casting of new characters, embedding identity politics and systemic exclusion narratives as key drivers of the second half's tension and resolution, though not the singular foundational premise.