A union chief descibed the scheme as "corrosive" and "nasty". iStock

British teachers have been left outraged after pupils in one UK school were enlisted into a "mystery shopper" style scheme in order to covertly judge their performance in the classroom and then provide "feedback" to senior leadership teams, it has been revealed.

The secondary-level educational facility, Longfield Academy in County Durham, started the secretive spy programme earlier this year and has described it as a way of bolstering the professional development of staff, the Times Educational Supplement reported.

"Secret shopper is part of a wider whole-school strategy that aims to celebrate success and promote sharing of good practice," explained Longfield head Susan Johnson.

"We are acutely aware that the pupils are our customers, and gathering pupil voice has always been important to us. However, in the past we have not always informed the pupils in advance that we would be asking them for their views.

"Trialling this strategy has enabled us to give the pupils time to consider what they would like their feedback to be." She claimed children were "proud" to be involved.

Johnson said that feedback received so far had been "positive" and asserted that it had backed up a number of the educational strategies already in use by staff.

But the Times Educational Supplement spoke with two teachers who were not convinced by the stealthy proposal, which was allegedly launched without staff consultation.

Both were granted anonymity in the report.

"We have to be seen as the authority in the classroom and we are giving the students the power to take that authority away from us," one teacher said. Another added: "They're not experts. The children cannot identify why you are doing what you are doing – they just don't have the nous."

The feedback from the pupils is provided to the faculty members in the last week of term.

An internal slideshow obtained by the Times Educational Supplement said the meetings had been dubbed "Customer Service Week" and would aim to "address customer dissatisfaction".

Mary Bousted, the general secretary of the Association of Teachers and Lecturers (ATL) union, said the "corrosive" and "nasty" scheme risked transforming the profession into a popularity contest.

"It's underhand, deceitful and it corrupts the proper order of relations in schools," she stated.