Primary schools are using surveillance cameras to track down and punish children behind classroom pranks.

The revelation is sure to add to the controversy surrounding the installation of the Big Brother-style CCTV and microphones in classrooms.

One school - Lynch Hill Primary in Slough, Berkshire - has even disclosed how it used the sophisticated equipment to identify an eight-year-old girl who hid her friend's shoes during a lesson.

The school has the cameras in 12 classrooms, three corridors, the school reception area, the music room and the canteen.

School bursar Lyn Hazell said: 'Someone hid a child's shoes and we found it on the tape so we knew where they were and who had hidden them.

'No one was owning up so we rewound the tape. If the teachers say, "I will rewind the tape," it makes them own up.

'The cameras are there as a deterrent. The parents are notified that the cameras are used. There are signs all around the school.

'It's not possible to opt-out and we have not had anyone saying they do not want to have them used.'

The girl who took the shoes was sent a warning 'yellow letter' from the school. Children who get three of these letters are suspended.

The 'victim' of the incident was a pupil named Lauren, also eight, who thought she had lost her favourite shoes - £13 black patent ballet pumps with a bow.

Her mother, Rosie Reardon, said: 'Her friend played a trick but Lauren did not find it that funny. She was quite upset.

'I'm quite glad there are cameras as they can help with situations like this.'

Lauren said: 'I was on the computer and I took my shoes off and then they were gone. I panicked a little bit. It was nearly home time.

'After they checked the cameras, my shoes were found in a locker. I was very happy to get them back.'

But the mother of the 'guilty' girl, who asked that her daughter should not be named, said: 'This use of the cameras is ridiculous.

'She took the shoes and hid them in a locker. We all do silly things and play jokes when we are children. They should have given her a chance - she's only eight.'

She said she had been in favour of the cameras being introduced to protect children but is horrified at how they are now being used.

'My daughter no longer wants to go to the school,' she said. 'The cameras have made her a bit panicky. Children should be taught to tell the truth without the use of these cameras.'

Classwatch, which markets the devices as a way to identify pupils disrupting lessons, is due to meet the Information Commissioner for urgent talks this week.

The data protection watchdog has the power to ban the equipment unless Classwatch and the 85 schools that have installed the system can persuade him its use is justified.

The Commissioner's office says use of this sort of system is 'deeply intrusive' and raises 'privacy concerns for teachers, students and their parents'.

Angus Drever, managing director of Classwatch, which charges £3,000 to install the system in each classroom, said it was acceptable for schools to use it to identify misdemeanours.

'My reading of the CCTV code of practice is there is nothing wrong in this,' he said.