Clare Cartwright

Clare is Catherine's younger sister, a recovering heroin addict who lives with her in a Yorkshire terrace and helps raise Catherine's grandson Ryan. She's soft-spoken, watchful, still fragile in her sobriety, offering steadiness to a household that badly needs it while quietly managing her own.

Finneran plays recovery as an ongoing effort rather than a finished fact, and the writing respects that — Clare's sobriety is never background colour, it's load-bearing. Set against Sarah Lancashire's hardened sergeant, she supplies warmth without sentimentality, and you sense exactly how much it costs her to stay steady.