As neonatal nurse Lucy Letby becomes the most prolific serial child killer in modern Britain, Gamal Fahnbulleh joins Mel Barham and Emma Sweeney to look at how she managed to slip under the radar for so long, carrying out her attacks at the Countess of Chester Hospital, unchallenged, for a year.

Lucy Letby will spent her whole life in prison after being found guilty of murdering six babies and trying to murder another six more.