Police dealt with 453 allegations of sex attacks on children in South Yorkshire in 12 months, new figures reveal.
The NSPCC says nearly a third of the victims, 144, were below secondary school age and another 44 were aged five or under.
Some 309 of the abused children who reported offences were aged between 11 and 17.
The NSPCC is calling for action to reduce the number of sexual assaults on children, with national figures revealing there were more than 400 offences reported to police every week between April 2010 and March 2011, but just one in 10 resulting in a successful prosecution.
Figures cover sex crimes including rape, incest and abuse of children through prostitution and pornography.
The NSPCC, which has 41 sexual abuse programmes across the UK, is calling for schools and parents to educate children about staying safe and reporting abuse and wants the Government to support the provision of therapeutic services for all child victims of sexual offences.
Gordon Ratcliffe, Regional Head of Service for the NSPCC in Yorkshire and the Humber, said: “A concentrated effort has to be made if we are to start reducing this distressing level of offences, many of which are committed on extremely young and helpless children.”
Det Insp Mark Monteiro, of South Yorkshire Police, said: “South Yorkshire Police deal robustly with child sex offence allegations and look for solutions which are in the best interests of the child.
“Therefore, it’s not necessarily accurate to judge the outcomes of all these cases just on the number of convictions.
“South Yorkshire Police work with partner agencies to safeguard children to look after their health and welfare.
“The Child Sex Offenders Disclosure Scheme is also active in the county, where concerned adults can ask police to check the backgrounds of individuals who have contact with their child.”