The vast majority of local education authorities allow children to be fingerprinted by their schools, new figures have revealed.

Data released to the Conservatives under the Freedom of Information Act show that only 39 of the 171 LEAs say they do not allow the practice.

This means that up to 17,000 thousand schools covering 5.9 million children may be allowed to request fingerprints, said the party.

And it warned that some schools are doing this without asking permission.

Shadow home affairs minister Damian Green said: "We need a code of practice to stop schools taking this most private information without even asking parents.

"We also need to ensure that the information is not available to hackers or outside bodies, and that the information will be destroyed when pupils have left the school.

"Schools use fingerprints as security for libraries, and sometime to allow access to canteens.

"If parents have given permission, this is acceptable, but only on strict conditions that every school should follow."

The Conservatives said there should be no fingerprinting of children without prior parental consent and any information should be coded so that no child can be identified by anyone looking at the school database.

Any information should be used only for purposes specified by the school in advance and the information should be destroyed when the child leaves the school, it added.

Liberal Democrat education spokesman Sarah Teather said the figures "confirm the extremely worrying state of affairs where schools are fingerprinting pupils without proper guidance on whether it is legal to do so".

"The government needs to respond to the concerns of parents and teachers and produce strict regulations for using this technology in schools," she added.

"An awful lot of people are washing their hands of responsibility of this issue while this practice spreads unregulated."