It was time for the final observation of my final PGCE placement at a tough primary in south London. I had a Year 6 class that was regarded as the school’s toughest. To make things worse, it was just after their Sats, so I was greeted by a daily wall of indifference and cries of: “Why do I have to be here?”

On top of that, the teaching assistant was heavily pregnant and I had been told on a pre-placement visit that the school requested a student so that she could have time away to complete her teacher assessment. I would go entire days without even seeing her.

Faced with all this, I had approached my placement with dread. As the weeks ticked by, I had gradually begun to make headway with the class and was able to get solid feedback from the first two observations. But on the day of my final observation, one child with challenging behaviour and attendance issues decided to come to school, giving me one more thing to think about.

The observation lesson was scheduled for after break. The English lesson before it involved drama work in small groups. I was floating around the groups, but watchful of the boy in question.

All it took was for my attention to be distracted for five seconds and the boy had stood up and punched another boy full in the face. I leapt over and grabbed the victim just as he was preparing a punch of his own, and struggled to hang on to a raging ball of anger. Both boys were hustled out of the class and I returned to shouts of: “You’re our hero” and applause.

At this point, I felt prepared for anything to go wrong, so I went into the observation lesson relaxed and was able to deliver a top-quality science session, with my observer and mentor both rating me good. In a bizarre way, that fight was probably the best thing that could have happened to me.

Matthew Walker is an NQT at Wormholt Park Primary School in west London.