Year 13 pupil Nadette Okon is one of ten sixth-form pupils trained by an Ofsted inspector to observe and evaluate her teachers.
"At first I thought it sounded a bit technical and I wondered if I would get the vengeance I desired," she joked.
"I felt a strange sense of empowerment as I realised my teachers were trying to impress me. It didn't make me big-headed though. I really learned a lot from it in many different ways."
Using the same criteria as regular Ofsted inspectors, pupils give staff a grade of between one and four - or excellent to unsatisfactory - for their efforts. They also give face-to-face feedback.
Their training, carried out by a serving Ofsted inspector, consisted of five after-school sessions, including what inspectors look for in lessons, evaluations of videotaped classes and mock feedback sessions.
The idea of pupils observing lessons is increasing in popularity, with schools keen to engage children in their education. But this is believed to be the first time that a school has sent its pupils for Ofsted-style training.
Daniel Griffin, an English teacher, was on the receiving end of one of the first pupil-inspector evaluations.
He admits it was a strange experience, but claims it was not intimidating or awkward - perhaps helped by the fact that Nadette graded him as excellent.
Mr Griffin was also observed during an official Ofsted inspection shortly afterwards and says the student inspection was more helpful. "Ofsted only look in for 15 minutes so don't get a full understanding of your lesson," he said. "Pupils know all the things that should be included. They already observe more lessons than an inspector ever could. It is a controversial idea and many teachers would probably not like it. But the pupils are observing the learning that goes on in a lesson, not just specific teaching techniques. Having been through it, I know it's beneficial."
The only time it would not work would be if a teacher was really struggling in their career or had classes that were particularly difficult to control, Mr Griffin said.
Chris Keates, general secretary of the NASUWT union, has criticised the idea of pupils observing lessons and interviewing staff, saying it undermines the profession.
But Roderick MacKinnon, Bexley's headteacher, said: "Teachers are happy with the idea that we can promote the quality of learning by listening more carefully to pupils, but one criticism was that they did not always know what they were looking for.
"So to add depth and rigour to the process we have had some of our students trained in the Ofsted manner, grades included."