CCTV surveillance has been set up in playgrounds, classrooms and even toilets and changing rooms. The average secondary school has 24 cameras and an academy 30.

Some schools have a camera for every five children in the name of controlling violence, vandalism and theft, the 'Daily Mail' reported.

In a development, that has already provoked outrage, more than 200 schools have CCTV operating in changing rooms or toilets.

The extent of pupil surveillance was made public in a report by 'Big Brother Watch', a watchdog group, which was based on Freedom of Information replies.

It found there are 106,710 spy cameras in secondary schools and academies across England and Wales – a quarter of the total used to monitor all of London's streets.

Big Brother Watch questioned how so many cameras have been set up without any check, what the recorded pictures were being used for, and who was watching them.

"The full extent of school surveillance is far higher than we had expected and will come as a shock to many parents," said Director Nick Pickles.

"Schools need to come clean about why they are using these cameras and what is happening to the footage. Local authorities also need to be doing far more to reign in excessive surveillance and ensure resources are not being diverted from more effective alternatives," he said.

Slightly under half of the cameras are mounted inside school buildings rather than outside, where they can be used to monitor potential intruders as well as pupils.

Typically, a school will have a camera for every 38 pupils – which means there are roughly two for every five teachers.

However, 54 schools have a camera for every 15 pupils and some there is a camera for every five pupils.

Top of the list for camera/pupil ratio is the Christ the King Catholic and Church of England Centre for Learning in Knowsley, Merseyside.

The watchdog group called for an independent review of school spy cameras.