All a child had to do to borrow Topsy & Tim for the week was flick a thumb through an unobtrusive fingerprint scanner, so sensitive it could even recognise a pattern from under layers of sticky chocolate.

There was only one snag: in many cases, parents were not told that schools were storing their children’s fingerprints.

Parental outrage followed and, by last night, the school thumb-scanner being used by 1,000 British primary schools was being internationally condemned as a blatant breach of children’s human rights.

The trouble began when the mother of an 11-year-old attending the Sacred Heart Roman Catholic School in Ruislip, West London, discovered that her son had been fingerprinted without her consent.

Furious, the woman, who refused to be named, contacted civil liberties groups such as Privacy International and a child’s advocacy group, Action on Rights for Children in Education (Arch).

Privacy International called for the banning of the library-management software, sold by a Stockport company called Micro Librarian Systems. “This is unethical and disproportionate,” Simon Davies, Privacy International’s director, said.

The assistant information commissioner Phil Boyd said that there had been no breaches of the Data Protection Act, as the thumbprints were reduced to a numerical code.