Anti-surveillance campaigners find average of 24 cameras in each secondary school that responded to the survey

More than 200 schools across Britain are using CCTV cameras in pupils' toilets or changing rooms, according to figures obtained by anti-surveillance campaigners, who warned that the research raised serious questions about the privacy of schoolchildren.

A total of 825 cameras were located in the toilets or changing rooms of 207 schools across England, Scotland and Wales, according to data provided by more than 2,000 schools.

The figures are based on freedom of information requests lodged by the campaign group Big Brother Watch. Its director, Nick Pickles, said the full extent of school surveillance was far higher than the group had expected, adding: "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 rein in excessive surveillance in their areas and ensuring resources are not being diverted from more effective alternatives."

The Radclyffe School in Oldham topped the list of schools with 20 cameras in toilets or changing rooms.

Responses from 2,107 secondary schools and academies showed they used 47,806 cameras overall, including 26,887 inside school buildings.

With 1.8m pupils being taught in these schools, there was an average of one camera for every 38 children.

In all, 90% of schools had CCTV cameras, with an average of 24 cameras in each of the 1,537 secondary schools that responded and 30 cameras in each of the 570 academies.

Big Brother Watch estimates the number of CCTV cameras in secondary schools and academies across England, Wales and Scotland was now 106,710.

Pickles also claimed that the Home Office's proposals for a new regulatory structure was "not fit for purpose" and that a new post of surveillance camera commissioner "will have absolutely no powers to do anything".

A Department for Education spokesman said: "We have already acted to make it unlawful for schools to use biometric data like fingerprints without parents' permission.

"CCTV can be beneficial in some cases but this is a decision that head teachers should take. Schools using CCTV are required by law to adhere to the Data Protection Act."

Sharon Holder, the GMB's national officer, said the trade union was appalled at the findings: "Placing CCTV in school bathrooms poses a worrying development in school policy and raises a number of questions. How many parents have given headteachers permission to film their child going to the toilet or having a shower? What happens to the film afterwards? How much discussion has there been on governing bodies and to what extent have councils and councillors had any input into these developments? What problems are the schools trying to solve?