A friend and I were chatting about how health and safety requirements and lengthy risk assessments can discourage teachers from taking classes on trips.

He described how, years ago, he had mislaid two children on an evening visit to the Albert Hall. In those days, risk assessment was a mere twinkle in the eye of future officialdom, but there were still simple checking routines to be done, like counting the children on to the coach - which is how he realised two were missing. In fact, they weren’t far away. They had been caught behind another party, but his heart had skipped a beat.

Which is certainly what mine did when I lost two children on the Circle Line of the London Underground. I had only been teaching for six months, and I wanted my Year 3s to visit the Tower of London. The deputy head came with me and everything had gone well, but we stayed too long and by the time we reached the station, rush hour had started. When we reached our stop, the deputy manoeuvred the children off the crowded carriage and on to the platform ready to count them.

As the train moved off I saw, with a horror that enveloped my entire body, the faces of Hergun and Murvette pressed against the glass of the train door, which was disappearing into the tunnel. Not only had the train taken two of my children, but they were recent immigrants with special needs. They had a mere handful of English words between them.

What to do? It was the Circle Line, so we knew the train would eventually return to the same spot, but that meant waiting an hour. And what if the two children hurried off in panic? Should I leap on to the next train and see if they were at the next station? After a hurried discussion, we decided that the deputy should walk the children back to school and I should alert the station master, who promised to telephone the staff at the next two stations.

I hung around, biting my nails with worry. Twenty minutes later he told me that the children had been recovered two stations on. “We’s lost,” they had told a passenger, who immediately took them to the booking clerk, who phoned the police, who were at that very moment taking them home, since Murvette knew the name of the road they both lived on.

Overcome with relief, but fearful of losing my job, I phoned the deputy. She said she would pop round to see the parents, adding that she was certain everything would be okay. When she arrived, Dad was sitting up in bed, clad only in vest and shorts, smiling broadly and sharing a huge portion of baked beans on a tin plate with his daughters. I didn’t sleep well that night.

Two years later, I managed a similar feat with a special needs child on the first evening of a school visit to the Isle of Wight. It was getting dark, but the children wanted a look at the sea. Back at the hotel, the children in Room 5 said that Sharon hadn’t returned. I suggested they look again, certain she couldn’t have gone far.

When she still couldn’t be found, I ran back to the beach, calling her name to the waves like a possessed Canute. Nothing. I hurried back to the hotel, assuming she would be there - but she wasn’t. I was just about to call the police when they arrived on the doorstep, with a very sheepish Sharon in tow. She had attached herself to the end of another school party, not realising in the darkness that it wasn’t us. The policeman wasn’t a happy bobby.

Now then, where did I put that pad of risk assessments?

Mike Kent is headteacher at Comber Grove Primary, Camberwell, south London. Email: mikejkent@aol.com.