I have never seen someone storm out of a lesson in quite such a rage. Admittedly, she was teaching the sex education course - never a casual stroll in the park - but it was clear that something far worse than unacceptable or inappropriate had happened this time around.

She burst into our team-room and was immediately on the phone - to her own mother, rather unexpectedly. Perhaps a few comforting words from home were in order.

But this was no ordinary call home. She was not seeking any motherly support and sympathy. She ripped into her.

We overheard that the lesson had been on childbirth and that she had been showing one of those standard-issue educational videos of a woman giving birth, full-on and unedited. After a few minutes, the camera moved to the other end and the teacher realised that the woman bringing forth was her own mother.

“Why the xxxx didn’t you ever tell me?” she raged down the phone. “I was the one who had to leave the room! Not any of them!” Her mother unsuccessfully tried to console her with assurances that the baby in the video was her sister, not her. This failed to placate her and the call ended.

The risks of classroom video

A colleague (male) cheerfully suggested to her that she perhaps look at the experience from a different perspective: wasn’t it perhaps rather beautiful that she could share that special family occasion with her class? The response was brief and brutal.

True professionals will argue that she should have watched the video first before showing it to the class. However, the old pre-recorded VHS tape in question had been happily doing the rounds for years. It was surely only reasonable for a busy new teacher just to pick it up and run with it?  

Besides, most of us were much more carefree in our use of videos at that time, back in the early 1990s. If we ever managed to book one of the school’s handful of video players for a lesson, goddammit we were going to make full use of that time slot, regardless of what the video was like. We would gratefully slap on grainy and seemingly endless old programmes about Gandhi, the French Revolution, Brazilian favelas or whatever. We could then sit back, confident that the droning voice-over would achieve its apparent aim of sending us all to sleep.

Everyone was happy with these occasional matinee lessons. Sometimes we might discover, mid-way through the documentary, that a colleague had inadvertently recorded an episode of EastEnders over the top of it, though no one much cared or noticed.  

The use of video in lessons is plainly much more effective nowadays. The digital age enables us to employ shorter, better-targeted clips. We now employ them as a stimulant rather than as a soporific - though we do need to choose carefully from the thousands of options out there now. I personally recommend stopping at any educational presentation on YouTube that begins with someone saying “Hi!”, as this is usually the cue for a mind-numbingly tedious presentation.

In fact, we should not paint too rosy a picture of class video-viewing today. Quite often, there is no picture at all. Most teachers reading this will suffer a mild medical reaction at the mere mention of graceless screen messages such as “This video is no longer available”, “Buffering”, “Access blocked - see your administrator” and “Check the air-filter”.

At least you knew that there would be something to watch when you shoved in an old VHS tape, even it did yield the odd surprise.      

Stephen Petty is head of humanities at Lord Williams’s School in Thame, Oxfordshire