Headteachers are set to incur the wrath of civil liberties campaigners after challenging new laws that would force them to seek permission from both parents to use children's biometric data.
The Association of School and College Leaders (ASCL) claims a new bill forcing them to gain consent would be a "huge bureaucratic burden" for schools operating technology such as fingerprint recognition systems for cardless libraries and cashless canteens.
The new Protection of Freedoms Bill also gives pupils in schools and colleges the right to refuse to give their biometric data and compels schools to make alternative provision for them.
The several thousand schools that already use the technology will also have to ask permission from parents retrospectively, even if their systems have been established for years.
Until now, government guidance has merely recommended schools explain to pupils and parents what they are doing, but seeking permission has not been obligatory.
ASCL says schools already running the systems with very few complaints from parents may see a surge in those deciding not to opt in. They also fear pupils may refuse to give their data just to make trouble.
Opponents of use of biometric data in schools - from iris scans to fingerprints - claim it can cause children to feel "criminalised" and leave them open to identity theft.
But ASCL's legal expert Richard Bird said: "The new law is based on a misunderstanding of what these systems are; it is not fingerprinting as understood by the police.
"The definition of `parent' is also complicated - in some cases there are up to five people with parental rights. It is very unclear.
"If there's a large-scale refusal to take part in these systems, schools who have invested a lot of money will have their plans turned upside- down."
ASCL general secretary Brian Lightman, who installed a fingerprint recognition system at his former school in South Wales, said giving parents the chance to "opt out" would be more sensible than the "opt in" arrangement in the bill.
"This isn't about storing data somewhere and infringing upon personal freedoms, it's just a very effective way of running things in schools.
"Having to get permission from every single parent will be a huge bureaucratic burden and very difficult to achieve.
"The existence of this clause itself in the bill starts to suggest to parents that there is something sinister behind this when there really isn't."
However, civil liberties campaigners have reacted angrily to ASCL's comments.
Daniel Hamilton, director of Big Brother Watch, said: "It's quite clear that schools are not properly equipped to hold this sort of unique and personal data.
"By taking it for trivial purposes schools are jeopardising the privacy of the students for the rest of their lives."
BIOMETRIC SYSTEMS - Picture perfect
Biometric systems are used by an estimated one in five schools.
- Common uses: automatic registration, cardless libraries, cashless canteens.
- Most popular systems: fingerprint-recognition.
- Other technology also in use: face and iris-recognition.