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