Pupils have been given iPhones to pass instant judgement on their teachers in lessons, a teaching union was told today.

The Association of Teachers and Lecturers heard that an unnamed secondary school in Kent gave the technology to around 20 students and asked them to send their comments to the head as part of a "quality assurance week".

But teachers raised concerns at the lack of transparency and staff being prevented from having the right to reply.

Backing a motion on pupil observation at ATL's annual conference in Manchester, John Rivers, an Information and Communication Technology secondary school teacher in Kent, told delegates: "There is a school in Kent brought to my attention by members where students during QA week are using school-issued iPhones to record their feelings during lessons." The comments were used to draw conclusions about the quality of learning, he said.

"How were the students chosen? What training were they given? Were they given carte blanche to comment on anything?" The teachers at the school did not know if they would be given a right to reply, or see the comments, Mr Rivers said.