A school in Cumbria has had two-way mirrors and a sound system installed in one of its classrooms to record everything taking place.
The aim is not to watch the pupils, but the teachers, to help develop and improve teaching practices.
The system at Nelson Thomlinson secondary school in Wigton is thought to be one of the first of its kind to be used in a school in the UK.
Pupils at the school have given the thumbs up to the new classroom.
'Bit nervy'
Head teacher Peter Ireland, who is behind the new system, said: "We are not concentrating on the kids, we are looking at the teacher.
"The main concern of any head is the developing of the skills of his or her teachers.
"You don't learn to be a teacher from a book, you learn through watching best practice form other practitioners."
One pupil at the school said of the special classroom: "When you first enter the room is a bit nervy but you get used to it."
Another said: "You just behave all the time because you don't know who is going to be in the room, whether it is the headmaster or another teacher."
Maths teacher Janet Downs said: "No member of staff will be forced to work in the classroom so everybody who goes in volunteers to be there, and the students are used to being watched because it is part of regular practice in the school."