At the time, it felt like an enormous risk: 1,400 students and staff assembled on the field for the school photograph. The company had said it was about the maximum they could squeeze on the staging for a single photograph. We had planned the movements of the tutor groups with a military efficiency that would have made Wellington proud.

There can be few teachers who have not woken up sweating in the middle of the night after their worst nightmare - that one where the class simply will not take any notice of you. The more you shout, plead, threaten, cajole, the more they think this is more fun than Jerry ever had with Tom.

Well, multiply that by 50 and you’ll get some idea of my school photo nightmare. What if it all goes wrong? Why do we continue to do such a last century thing?

The reason can be summed up in a single word: belonging. We know that young people need to feel they belong to a group, and that in an era of increasingly dysfunctional families, greater mobility and looser communities, that need becomes greater. Our regular student surveys ask:

“Do you feel you belong in the college?” About 90 per cent say they do, which is great but leaves us with the problem of how to engage the remaining 10 per cent. We have tried hip hop dance and graffiti art; all Year 7s go on a residential, all Year 8s on an arts day; Year 11 create a year book; and we increasingly personalise the curriculum, including plenty of work-related learning. Belonging also comes through communal celebration. With Harvest festival and sports day long gone, tag rugby, Pop Idol and Battle of the Bands have taken their place. But the school photo still makes its own small contribution.

So there was a mood of anticipation as we all assembled, a sense of event and an shared naughtiness that we were all bunking off for the afternoon to do something faintly frivolous. A few fire-eaters and whelk stalls would not have seemed out of place. We all wanted to be there - and how often can that be said of school?

Of course, one girl had to be ferried to hospital with suspected concussion, Rory thumped Shaun, a sixth former did a moonie. Then, finally, everyone was standing quietly waiting to say cheese. Until Eric performed.

You will remember Eric from a previous column. He’s Andy the biology teacher’s dog, who was banned from the college after his barking disrupted one lesson too many.

I still get emails asking after him from Sarah at the Department for Education and Skills, which just goes to show that Sanctuary Buildings is run by humans, not computers, after all.

Anyway, Eric had returned for the photo and was obediently trotting around with a school tie round his neck. Suddenly 1,400 shrill voices and outstretched arms were pointing at him performing his prolonged doggy function right in front of the entire college. I glared at Andy, he glared at Eric and 1,400 people wondered what was going to happen next. Andy scurried off, came back with two supermarket bags filched from the bin, gave an instant lesson in good citizenship, bowed and received a huge round of applause in return.

Since the final photo went on display in reception, there have been constant knots of students around it pointing, smiling and remembering.

Eric sits proudly in the front row, the Lord of Misrule, who reminds us of the most powerful binding force behind belonging: laughter.

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