Sarah Payne was murdered by a convicted sex offender
A pilot scheme allowing parents to check with police if someone close to their children has a history of child sex offending is being expanded.
Forces received 79 official requests for information in four trial areas, and disclosures were made in 10 cases.
Coverage will now be extended across Cambridgeshire, Cleveland and Hampshire, where it had previously operated only in parts of the counties.
The scheme will continue in the entire Warwickshire area.
The project has been backed by the government's Victims' Champion Sara Payne, whose eight-year-old daughter Sarah was abducted and murdered by convicted sex offender Roy Whiting.
The case had prompted calls for a British "Sarah's Law", based on the so-called Megan's Law in the US which allows the publication of names, addresses and pictures of paedophiles in some states.
But some charities have said they are concerned the scheme could spark vigilante attacks or drive offenders underground.
Under the scheme, parents, carers and guardians can ask police to tell them whether people who have access to their children have a record for child sexual offences.
HOW DOES IT WORK?
Parents, carers or guardians can ask the police if someone who has access to their children has a record for child sex offences
Grandparents could alert police about concerns, but information only goes to those with direct responsibility for the children
Officers do a priority check within 24 hours, followed by a more thorough risk assessment
If convictions found, police work out how to deal with it. They assess if disclosure needed, depending on risk to the children
If police unearth something, they may not disclose it if they decide the person does not pose a risk
Parents and carers are asked to keep information confidential - and could face action if they don't
If the person is found to have convictions, and poses a risk of causing serious harm to the children concerned, this may be disclosed and action is taken where necessary.
While there is a presumption of disclosure, it only happens where police decide it is "necessary and proportionate" to protect children.
Where information is given, parents and carers are asked to keep it confidential, and could face civil or criminal action if they do not.
Of the 79 applications made in the pilot scheme, details were disclosed on 10 individuals - five in Warwickshire and five in Cleveland.
In one case information was passed on about a man with access to his new partner's grandchildren.
He had previously been investigated for child sex abuse and convicted of sex offences against adults.
In another example police were contacted by a parent concerned about the behaviour of a family friend.
They discovered the man had apparently breached a court order that should have stopped him being alone with children, and he was arrested and charged.
Paul Cavadino of the charity Nacro, which works to rehabilitate offenders, said he still had reservations about the project:
"Clearly if this is managed well it could protect children by telling parents that somebody who has a history of sexual offences is targeting their child.
"The risks which have to be assessed by the pilot are essentially about whether that information would leak out into the wider community from the parent."
He said other than the risk of attacks it could also cause the offender to go to ground by changing his name, moving around, or opting out of probation supervision, "thereby increasing risk to children".
Police say there have so far been no cases of vigilante attacks against offenders.
Warwickshire Chief Constable Keith Bristow, who speaks on violence and public protection issues for the Association of Chief Police Officers (Acpo), said: "Extending the pilot sites across the forces will allow better evaluation on which to base future decisions.
"The police service is committed to protecting children from any individual who poses harm or risk and the pilot has assisted in raising public awareness of child protection issues.
"For those parents and carers who have made enquiries, we trust that it has helped give them confidence that their children are safe."
Home Secretary Jacqui Smith said the pilot projects had given children a "better deal".
After one year the government will assess whether to expand the scheme across England and Wales.