A computer system to allow police forces to quickly share information about suspects has been launched.
Police will have access to records via an internet-based search facility
The initiative is a response to the Bichard inquiry into failings that allowed Soham murderer Ian Huntley to work as a school caretaker.
Officers can now search online every record held by forces in England and Wales on a particular person.
Police minister Hazel Blears welcomed the Impact Nominal Index saying this would "help create safer communities."
Detective Chief Superintendent Peter Spindler, who heads the Metropolitan Police's central child protection unit, said: "I have no doubt that we will be saving people's lives. We have already stopped putting children in areas of risk."
The Home Office said it had already thrown up leads in investigations.
One search linked a person alleged to have committed an indecent assault on a 15-year-old girl to an identical case in another force area.
A check on a man acquitted of assaulting his girlfriend's eight-year-old daughter found he had been linked to identical incidents in five other forces.
The system uses information which every force in England and Wales sends to the Criminal Records Bureau (CRB) - a list of names and dates of birth of people - which the forces hold for use in vetting checks.
Officers can call up a list of every record held around the country on a particular person.
They can then phone the police force holding the record and ask for more details about what it contains.
The system currently contains 32.5 million records, while in the five weeks since it went live, there have been 3,000 searches.
Child Abuse Investigations Units in all 43 police forces in England and Wales have already been given access to the INI database.