A controversial database featuring the details of every child in England has become available to childcare professionals today.

Up to 800 social workers, head teachers and health officials will be able to use the new system, called ContactPoint, as it begins its national roll-out in the north west. Eventually, the system will be rolled out across the country.

The system, which cost an estimated £224m has been dogged with data security fears and has been delayed twice due to faults.

ContactPoint has also come under heavy criticism from civil libertarians. A report written by information policy experts at Joseph Rowntree Reform Trust described the database as "almost certainly illegal", and warned that storing information leads to vulnerable people, such as young black men, single parents and children, being victimised.

In 2007, Deloitte and Touche said in a report that the project could never be totally secure.

In March, the launch was delayed after a fault sometimes exposed the information of vulnerable children, including victims of domestic violence and those in witness protection schemes.

But Ed Balls, the Children's Secretary (pictured) said there has been "important and careful work" to build ContactPoint over the past four months.

"If we are to do our best to make sure children are protected and that no child slips through the net, then it's crucial the right agencies are involved at the right time and get even better at sharing information," said Balls.

"ContactPoint is vital for this because it will enable frontline professionals to see quickly and easily who else is in contact with a child."

It has been welcomed by children's charities and organisations, including Barnardo's, KIDS and the Association of Directors of Children's Services. Martin Narey, chief executive of children's charity Barnardo's, said it "would make it easier to deliver better-co-ordinated services".

ContactPoint, built by Capgemini, is described as an "online tool" that holds "minimal" identifying information of around 11 million under 18 year olds in England, including names, addresses, dates of birth, gender and contact details for parents or carers. Each child is also given a unique identifying number, as well as contact details for the child's school, GP practices and any other practitioner services involved.

The database is only intended to be accessed by professionals working with children, such as social workers, doctors and the police, and the government has said users cannot download the contents from ContactPoint.