Lucy Letby: The Killer Questions

File on 4 examines some of the most contentious statistical, scientific and medical evidence in the Lucy Letby trial. The programme reveals new concerns involving medical evidence presented in court where Letby was convicted of murdering seven babies and attempting to murder seven others.

Reporter: Stephanie Hegarty Producers: Fay Nurse, Ben Robinson and Hayley Mortimer Technical Producers: Richard Hannaford and Nicky Edwards Production Coordinator: Tim Fernley Editor: Carl Johnston