Learning curve: Sammy Wright, left, with Conrad Landin [Katia Wengraf]

ONE summer’s afternoon in 2007, a class of unruly 15-year-olds cascaded into a battered classroom at William Ellis School, Highgate, to the news we were getting our third English teacher of the year.

The first had been a well-spoken former BBC radio journalist, who had come in with dreams of inspiring comprehensive kids with a love of literature, only to resign after his life was made hell.

The second, a jaded Australian with a string of beads round his hairy neck, was resigned from day one – to the reality of never being able to control our class.

The third, however, told us we would not write a single word in our exercise books for the final six weeks of the year. And he kept his word. Instead, we read the sci-fi novel Flowers for Algernon, watched Blade Runner and spent hours debating the ethical questions I’d never quite realised literature could open the door to.

That teacher was Sammy Wright, the author of Exam Nation, a book investigating just what is the point of school. Now a headteacher in Sunderland, he’s been teaching for 20 years.

Anyone who’s entered his classroom will know he’s got a gift for the profession, but it’s clear he’s been troubled by his time in schools too. When hopeful, he tells new teachers that their role is “a sprinkler, not a hose… spraying across as wide an area as possible, in the hope that some random drop of knowledge hits a seedling that you weren’t even aware of”. In his “grimmer moments”, he thinks that teachers are “agents of the status quo, trained to weed out those who don’t fit into neat rows”.

Across 250 pages of sparkling prose, Wright discusses teaching styles, curriculums, exams, exclusion and personal development. We haven’t got a system that works, he argues, because secondary schooling is a very new concept, at least when applied to the whole population.

Primary schools offer a “universal” education “a lot of the without [ability] sets, a lot of the time about lifting the whole class to the same level, understanding the local community” he elaborates when I interview him at Mount Florida Books in Glasgow.

“As soon as you get into secondary, it fits the mould of a selective, academised education. And that is simply because what we think of as secondary schools are simply an evolution of grammar schools. That’s how it happened. A comprehensive school isn’t a secondary modern that’s evolved – a comprehensive is a grammar school that’s evolved.

“So why haven’t we got it right? It is genuinely that we haven’t figured out what we want schools to do, and that is why we don’t have a system that has got a real, clear structure to it.”

Wright’s enormous patience, here and elsewhere, is both admirable and frustrating. Surely the vast array of different school types and educational pedagogies leaves some kids getting a lower standard of learning than others?

He is perhaps cautious in some areas – he calls for extra taxes on private schools rather than their outright abolition, for instance – so he can be more radical in others. GCSEs, he argues, “are the major problem at the heart of our system”, with the maths curriculum “designed to funnel students towards the academic study of maths rather than to provide general competence”.

He advocates instead for a “passport qualification” to be sat at 15 with no choice of subjects, but an independent project which assesses not content but the process of developing knowledge.

In spite of its title and sub-title, Exam Nation is not an indictment of exams or a call for their abolition – but rather a plea for us to value them less. It takes some bravery to argue that exams should be less accurate rather than more, but that would at least mean we stopped basing the worth of human beings on a series of silent sessions in school halls they experienced as teenagers.

More than anything else, Exam Nation is formed of Wright’s interactions with schools and their communities: teachers, pupils and Wright’s own former pupils – including me. He has criss-crossed the country in search of all kinds of schools and kids, but it’s clear his time in north London has left its mark.

“Ellis boys,” he writes, all had “a particular quality: a hectic warmth, a bullish sensitivity”. He continues: “They’d behave in ways that were halfway between the impish mischief of a Beano comic and the charismatic menace of Tony Soprano – but always with an implicit acknowledgment of the school as a tight community, and of teachers as people you trusted, even as you mocked them. ‘F*** off, sir’ was a classic Ellis phrase.”

I can’t deny having thought it once or twice – though never towards Mr Wright.

• Exam Nation: Why Our Obsession With Grades Fails Everyone and a Better Way to Think About School. By Sammy Wright. Bodley Head, £22