Commander Anne Sampson

Commander Anne Sampson runs Counter Terrorism Command with brisk, unshakeable authority, weighing political pressure against operational judgment at every turn. She oversees Sergeant David Budd's protection duties, trusts him more than she probably should, and moves through Whitehall's competing agendas with the calm of someone who has learned never to show which way she's leaning.

Gina McKee plays Sampson as pure procedural steel, giving almost nothing away in her face while the plot churns around her. That restraint is the point: in a thriller full of people lying to protect themselves, she reads as the rare figure genuinely trying to do her job properly, which makes her judgment calls feel like the show's moral ballast.