Security flaws have halted work on the internet database designed to hold the details of 11 million children and teenagers.

The Department for Children, Schools and Families (DCSF) admitted last night that it had uncovered problems in the system for shielding details of an estimated 55,000 vulnerable children.

These include children who are victims of domestic violence, those in difficult adoptions or witness protection programmes and the children of the rich and famous, whose whereabouts may need to be kept secret.

ContactPoint is a £224 million online database that contains the names, addresses, dates of birth and details of schools, GPs, social workers and support services of all 11 million people aged under 18 in England. It is intended to improve child protection.

The project has been dogged by controversy since its inception in 2003 and the loss of many big databases has dented public confidence. ContactPoint was supposed to go live nationally this year but a spokeswoman for the DCSF said that the department had ordered a “pause in the ongoing data update” pending an investigation into the shielding problems.

The shielding system for vulnerable children is supposed to withdraw everything but a child’s name, sex and age from the computer record that will be available to 400,000 children’s services workers with access to the database. But local authority staff who have been uploading information on to ContactPoint have discovered that the shielding does not always work.

Some adopted children whose identities should be shielded are listed on the database by both their original and their adopted surnames, with a link between the two. This could allow children who have been removed from abusive homes and put forward for adoption to be tracked down by their birth parents.

In other instances, shielding simply disappears from the records of vulnerable children every time that the database is updated automatically from central government databases, such as the school census or the child benefit database. This leaves all their details visible on a duplicate record that appears, as if from nowhere, on the database.

Anne Marie Carrie, the executive director of family and children’s services for the borough of Kensington & Chelsea in West London, said that these problems had arisen in a number of authorities, including her own. Ms Carrie’s staff entered the details of 130 adopted children in the borough on to ContactPoint. In 20 cases, or 15 per cent of the total, a duplicate entry containing the child’s birth name appeared on the database.

“If someone wanted to maliciously track down a child they had given up for adoption, this would make it easier for them to find their address and school,” she said.

She knew of other authorities, where shielding protection for vulnerable children had been overridden as soon as their records had been updated by the health service or the Department for Work and Pensions.

“Some people are seeing this as an IT issue but, in reality, it is a child protection issue,” she said.

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