All I needed to qualify for a teaching job was a clean record, an honours degree and a smattering of teaching experience in any subject: mine was in teaching English as a foreign language. It didn't matter that the last time I was in a school was when I was a pupil. So in March I registered with a privately run recruitment agency for supply teachers.

All I needed to qualify for a teaching job was a clean record, an honours degree and a smattering of teaching experience in any subject: mine was in teaching English as a foreign language. It didn't matter that the last time I was in a school was when I was a pupil. So in March I registered with a privately run recruitment agency for supply teachers.

Six weeks later I found myself at an inner-city comprehensive in Leeds for a week, expected to do drama, French (I speak about 10 words), English and art. If this was a nasty surprise, the chaotic corridors were even more of a shock. As I was shown round, students were spitting, shouting abuse and pulling faces at one another - and at the teachers.

Approaching my classroom for my first lesson, I saw 30 boys and girls rioting outside. This was a year eight drama class of 12- to 13-year-olds. A lesson plan had been left in my classroom: it was four lines long and there were no handouts. There were no whiteboard pens or erasers, pens, pencils or spare paper.

When all the students had taken their coats off, sat down and I'd tried to get some sort of decorum - this took 15 minutes - I introduced myself and started a lesson on fairytales and physical theatre, subjects I knew almost nothing about. Then in the corridor I heard the most awful screams. Another teacher, totally exasperated, was roaring expletives at a student. There were other students screaming at him in turn. Some of mine ran out and joined in. Then, for the next 20 minutes it was impossible to regain control: chairs were thrown, there was fighting, swearing, students were hanging out of the third-floor windows, throwing other students' coats, pens, pencils and work out of them, sometimes aiming these objects at teachers below. By the time the lesson was over, I had been told to "fuck off" repeatedly, and a student had threatened me with a pair of scissors. Work-wise, nothing had been accomplished.

The noises and scenes in the corridors were more reminiscent of a Victorian lunatic asylum than a school. It was quite normal for students to walk out of my lessons, and for truanting students to come in and disrupt them.

My final lesson of the day was disrupted by a 15-year-old boy truanting from another class. He came in and dragged one of my students out by his hair, who was screaming and crying. There was little I could do, as you can't touch a pupil. When I asked a well-behaved student to get help he was threatened and wouldn't go.

The school was run-down, and I suspect it has no choice but to accept inexperienced, unqualified teachers like myself, when what it really needs is the exact opposite. On my second day, the head of department told me she was pleased to see me back, as many supply teachers don't return. One can only be in awe of the teachers who work in this environment: they are under-resourced, overworked, abused and threatened daily, and still, in general, show an enormous amount of goodwill and care towards their students.

The most tragic aspect of this is the effect it has on those children who ignore the chaos. There are five or six in every class who know that hard work is their only chance to escape. After being hit, spat and sworn at, bullied and abused, this type of student often asks, timidly, at the end of a lesson, for a good behaviour slip. It's the least anyone could do, but shouldn't we be doing more?

Tristan Moss lasted four days at the school. His next job was no better. He now works as a freelance writer