Police recorded 50 child sex offences in England and Wales every day last year, meaning children were victims of sex crimes on more than 20,000 occasions, according to research by a charity.
The National Society for the Prevention of Cruelty to Children (NSPCC) said the figures showed that in nearly one in four cases victims were under 10 and more than 800 incidents involved children aged four and under.
NSPCC director of public policy Phillip Noyes said the statistic painted a grim picture but warned they were only a snapshot and that many cases of abuse never came to light.
"These shocking figures reveal just how young many of the reported victims of sex abuse are, with even one-year-olds being at risk, although the highest numbers of offences were against children in their early teens," he said.
"Clearly, very young children who are sexually abused can't speak out and it's currently very difficult to get a clear understanding of how many child sex abuse victims there are."
The 2008 figures, obtained from 42 of the 43 police forces in England and Wales using the Freedom of Information Act, showed there were 20,758 cases where victims of sex crimes such as rape and gross indecency were recorded as being under 18.
Victims were 10 and younger in 4,984 offences and in 163 incidents, they were aged just one or two. The number of offences involving girls was six times higher than those recorded against boys.
The NSPCC said the government needed to change the way it collected and published official data saying the Home Office mixed adult and children's statistics and so failed to give a clear picture of the extent of the abuse.
"If we are able to get these details every year it will start to build a more accurate picture of what is happening and we can make more concerted efforts to protect children," Noyes said.
The Home Office said it was committed to bringing more sex offenders to justice and had spent 11.25 million pounds in the last five years on support services for child and adult victims.
"We now have specialist child abuse investigation teams and specialist rape prosecutors in every area and provide operational support to forces to help improve their strategies for the investigation of serious sexual offences," a spokesman said.Reuse content