More than a third of all sex crimes are committed against children, figures showed on Wednesday.
A child was sexually attacked every 20 minutes last year, with more than 60 child sex offences reported to police every day.
Some 23,000 children - more than a fifth of them too young for secondary school - were victims of sex offences in England and Wales during 2010/11, the police figures showed.
But fewer than 10% of reported child sex offences ended in someone being sentenced.
The statistics, obtained by the NSPCC in a freedom of information request, cover crimes including rape, incest and child prostitution across all 43 police forces in England and Wales.
The charity said they showed a major effort is needed to protect vulnerable children and urged the Government to treat the issue "as seriously as they would if faced with an outbreak of chronic disease".
Overall, there were 54,982 sex offences last year, including 23,097 against children, the figures showed.
Most of the children (14,819) were aged between 11 and 17, including 8,749 aged 13 to 15. There were 4,973 victims aged 10 and under, including 1,472 who were younger than six.
And six times as many offences were committed against girls (19,790) than boys (3,218).
Britain's biggest force, the Metropolitan Police, received the highest number of reports (3,420), followed by the forces in Thames Valley (1,264) and West Yorkshire (1,170).
Jon Brown, head of the NSPCC's sexual abuse programme, 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.
"When you have a situation where more than 60 children are being sexually abused every day, something is very wrong.
"The Government has to start treating the situation as seriously as they would if faced with an outbreak of chronic disease."
He went on: "We also need a clearer picture of what is happening between an offence being reported and someone appearing in court.
"The police are doing their best to bring prosecutions but we need to understand why there is such a huge disparity between the two figures.
"It requires a major effort from Government and the public to give children the protection they need and to provide more therapeutic programmes so the young victims of abuse can start to rebuild their lives."
A Government spokeswoman said: "The Government is determined to protect children from sexual abuse and will continue to work across departments, law enforcement, agencies and charities in order to do so.
"We are tightening restrictions and closing loopholes to strengthen the sex offenders register and have set out a detailed action plan to tackle child sexual exploitation.
"We have run teen abuse and consent campaigns and we are investing £1.2 million over the next three years to improve services for young people affected by sexual abuse and exploitation."
She went on: "While both the number of convictions for sexual offences and the average length of sentences have increased significantly in the past year, we know there is more to do.
"Everyone has a role to play in keeping our kids safe and parents, friends and family need to be alert to possible warning signs of abuse and know where to go for help."
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