I loved teaching. On a rare night out with other teachers, I talked shop incessantly. But all that changed on a sunny morning a few weeks ago when I was the victim of a random act of violence. It was lesson two on a Monday. I was happy and confident, cajoling my second Year 9 class of the day.

I had taught the new boy - let’s call him Tyson - only once before. I noticed he had his mobile phone out so told him to put it away. He did so. Then, 10 minutes later, I saw that he had it out again.

I was not angry. I did not raise my voice. However, this time I took the phone off him. He removed the battery first, but he did hand it over.

Yet before I had made it to my desk he was out of his seat. He refused to sit back down. He wanted his phone back.

Instinctively, I felt his response was not the norm. His was not the “I’m-going-to-grumble-but-I-know-it’s-a-fair-cop” reaction. I decided to lead him to the classroom next door to sit him with my head of department, but she was busy taking mock orals.

I told Tyson that unless he sat back down I would “level 4” him (our school’s ultimate sanction where a senior member of staff removes a pupil). He began to walk back into the classroom and I thought the crisis was averted.

What happened next was over in seconds. Tyson thought it would be a good idea to take my bag hostage. He grabbed it, wielding it provocatively in front of him, and swore at me. Some of the class were amused, shouting “He’s got miss’s bag!”; some were shocked, all were watching. I had no control.

Then, bang! Seconds later Tyson had me pinned up against the board. He attacked me viciously and unrelentingly, swearing at me and promising he would knock me out.

The instinct for fight or flight kicks in at moments like these, but I felt I could do neither for fear of my job. He had me by my wrists. Eventually I did try to kick him off, full of anguish in case I might bruise him. It was only when another teacher entered the room that the attack stopped. I had never imagined how relieved I would be to hear the words: “Tyson, I am going to have to restrain you.”

The random act left me bruised down my right side and shocked. Over the next few days my mind raced over events again and again. I gave a statement and was told that I could bring charges. I chose not to - I was frightened I might end up the villain somehow and accused of harming a child.

I coped well for the first few days after the attack, determined to be strong. Every time I saw a phone, I confiscated it. No chances. Instead of avoiding potential conflict I instinctively sought it out. The “random act” had uncovered my inner Clint Eastwood. I was trigger-happy and itching for a fight. Things that had hitherto irritated me mildly now sent me into a rage.

Another teacher’s Year 10 class, eating and listening to music on their iPods with their phones out on the desks, made me livid and I would rant when I got home.

One week later I went in to teach the same class where the attack had happened. Some pupils were kind, most the same as usual, but one previously quiet pupil saw me as fair game and did no work.

None of those pupils had come to my help when I was attacked. I survived the lesson but broke down as soon as it was over. The exciting challenge of teaching has changed into a nightmarish battle. I don’t know if I have the stomach for it any more.

The writer has chosen to remain anonymous. If you have an experience to share, email features@tes.co.uk.