Kentucky Fried Chicken. Blackpool Pleasure Beach. Vodafone’s complaints call centre. These are service sector enterprises, businesses that do well if they live by the mantra that the customer is always right.

It may seem like stating the obvious, but it’s worth repeating now and again that schools are not in the service sector.

KFC, the funfair, whatever mobile operator you’re enslaved to, even TES: they all have business models that should zero in on keeping their customers satisfied, not making them better people.

This delineation is one short cut when deciding which sectors should be owned privately - British Leyland and British Airways, for example - and those that shouldn’t - the National Health Service, the labour exchange, the probation service (take note, Chris Grayling).

In case you hadn’t noticed, schools fit neatly into the latter camp. In their very simplest form, they exist to make their students better, more educated people. What they don’t exist to do is to make their students happier per se. Students are not customers and they are very definitely not “always right”. If they enjoy school, that’s great, but it’s not education’s raison d’tre.

This is one reason why the news that nearly two-thirds of schools globally - or at least within the 65 countries that participate in the Programme for International Student Assessment - require written feedback from students about lessons, teachers or resources is so galling.

Of course there is something to be said for encouraging a limited degree of student voice. If a school’s lavatory provision needs to be reorganised because it incubates bullying then the student body is best placed to bring this to the attention of senior staff.

On this level, it is admirable to have open communication channels - good for the school and good for the students who want to get involved. But children should certainly not be judging teaching standards or, God forbid, interviewing potential recruits. Without wishing to resort to a hackneyed expression, teacher does know best; this belief should remain at the centre of education systems everywhere.

Give most young people the right to influence their teachers or the content of their lessons and they’ll understandably opt for entertainment or anarchy. They are, after all, children and will always assume that fun lessons are good lessons, which many teachers would point out is not reliably the case.

The rise and rise of student voice comes in an era when performance pay is coming to prominence. We are surely close to the moment when some poor teachers have their pay packets influenced by what Class 4B thought of their lesson on the Vikings. Madness.

Please don’t mistake this as some kind of negatively conservative rant against liberal values. This is a positive argument in favour of teachers, of their professionalism and of their public service. They are a group of people who increasingly strive to maintain the highest standards.

To suggest that teachers’ success or failure in this endeavour should be decided by whether Little Jonny enjoyed learning about quadratic equations is to render them no more important than a call centre customer service assistant.

ed.dorrell@tes.co.uk.