The UK's Sex Offenders Register is failing to protect vulnerable children, according to a psychologist at the University of Liverpool.

Researchers say that while police are using their resources to combat Internet sex offences - which are much easier to secure convictions for - the majority of men alleged to have directly sexually abused a child are still avoiding prosecution. Currently only one in 10 men alleged to have committed a sex offence with a child is on the Sex Offenders Register. This, says Professor Kevin Browne, is leaving vulnerable children open to unmonitored paedophile predators.

Professor Browne, who is a forensic child psychologist, said: "This makes the debate on notifying communities of registered sex offenders meaningless. Adequate police resources are being used to detect Internet sex crimes where computer evidence of men downloading child pornography is easy to obtain and easier to secure a conviction for. But UK research shows that only six per cent of those arrested are linked to the much more severe sexual assaults on children.

"The compliance level for offenders on the Sex Offenders Register is high, with 97 percent notifying police of their location details. The problem is that with a conviction rate of less than 10 per cent for alleged contact sex offences, more than 90 per cent of men at risk of molesting children are essentially at large and unmonitored.

"The police need more funds to combat sex offenders who directly sexually abuse children. With additional resources available, more police time can be spent securing convictions and effectively monitoring convicted sex offenders in the community. This investment could reduce sexual assaults on children throughout the UK.

"Official statistics put the number of child victims of sexual abuse in England at two in every 10,000 but an NSPCC survey of young adults' childhood experiences shows the figure to be a lot higher at 11 children in every 100. This suggests that most sexual assaults on children go undetected and for every one child identified as a victim of sexual abuse there are 549 child victims who have suffered in silence.

"Most men who directly assault children do so in secret which makes contact sex offenders difficult to convict and without more police resources to tackle this problem the Sex Offenders Register will remain of limited use for the protection of children. On average, child molesters in prison admit to six years of undetected contact sex offences before their first conviction".

Professor Browne added: "Police resourcing issues are compounded by the fact that any person convicted of a sexual crime before the implementation of the Sex Offender's Register in 1997 is not required to register. These men may be unknown to the authorities today."