Chief Supt. John Deakin

Chief Superintendent John Deakin sits high in the police hierarchy that Between the Lines' Complaints Investigation Bureau exists to scrutinise. Smooth, watchful and thoroughly political, he treats internal investigations as a game of institutional survival, always a step ahead of the officers sent to hold him to account, and never quite showing his hand.

Tony Doyle plays Deakin with the unhurried confidence of a man who has learned exactly how power moves inside an organisation, so every scene becomes a quiet contest of who is manipulating whom. The writing never tips into cartoon villainy; it lets ambiguity do the work, and Doyle's stillness makes that ambiguity genuinely unsettling.