Panorama investigates a hidden world of child sexual abuse, one in which children sexually assault other children. It's often referred to as 'peer-on-peer' abuse and can happen in classrooms and even in theplaygrounds of primary schools.In this part-animated film, children, interviewed anonymously to protect their identities, talk candidly about the abuse they have experienced and describe how they felt let down when they tried to report it. The programme also speaks to some parents who say they struggled to get help from schools, social services and the police.Using freedom of information requests, the programme reveals an increase in sexual offences carried out by under-18s on other children and a dramatic rise in sexual assaults committed by children even on school premises.