LONDON — At the King Ecgbert School in Sheffield, teens who go to the loos are never really alone — video cameras are inside all 12 bathrooms.

Citing findings gathered via freedom-of-information requests, privacy activists today identified King Ecgbert as one of more than 200 high schools across Britain that have installed surveillance cameras in bathrooms or locker rooms.

The group behind the report, Big Brother Watch, said a powerful watchdog is needed to ensure that students’ privacy is protected.

The report “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.”

Lesley Bowes, King Ecgbert’s principal, argued the cameras help keep her students safe.

“It’s a way of safeguarding our children,” Bowes said. She described her school’s cameras as useful anti-bullying tools. And she rejected any suggestion that the recording captures the students’ most intimate activities, saying the cameras monitor just the doors.

“The cameras are nowhere near the toilet cubicles,” she said.

A total of 207 high schools across England, Wales and Scotland acknowledged installing cameras in bathrooms and changing rooms, according to Big Brother Watch.