Guest Stars El Anthony as Mark De Costa Deka Walmsley as DCI Mick Wickerson Jonah Collier as Young Robert Napper Anya Cooke as Young Napper's Sister Natasha Jayetileke as Newsreader Jack Riddiford as Robert Napper Anna Tierney as Samantha Bisset Simon Kunz as Justice Ognall Simon Armstrong as SIO Micky Banks Jasper Jacob as John Nutting QC Adam Loxley as Camping Man Simon Wilson as Jim Sturman QC Crispin Letts as Psychotherapist Susan Gillias as Female Prison Officer Mark Ellul as Prisoner 2 Michael Ukandu as Prisoner 1 Alexia Russell as Jazmine Bisset Nick Malinowski as DS Alan Jackaman Bruce MacKinnon as William Clegg QC