My moment of truth came several years later, and in the most unexpected of places. For the third year running I was leading an expedition of 17-year- olds in the mountains of southern Iran. We had been moving with the nomads on their annual migration. One evening the tribal chief, a Bedouin, who closely resembled pictures of Abraham I remembered from Sunday School, asked through an interpreter for permission to put an awkward question to me. I assented readily. ‘Tell me,” he said, “we appreciate these fine young men you have brought from distant England. But we have a difficulty. Why are they not in their own homes, working alongside their parents, learning the wisdom of their elders as they work?”

He was right. It WAS an incredibly awkward question to answer – the culture gap was just too great.

I would have forgotten all this, however, had it not been for another conversation an hour or so later. One of the boys, a tough lad from Oldham in north Manchester, came to see me. He was distressed. Something was very obviously amiss. “I heard the question the chief asked you. It really hurt me. I’m sure my dad loves me but I hardly know him. You see, when I get home in the evening I’m too tired to talk much. And my dad gets so tired in his job that he rests or sleeps most of the weekend. I know he loves me and my sister, that’s why he works so hard. But there’s an emptiness in my life; I just don’t seem to know my Dad. I feel like I’m incomplete.”

I’ve never forgotten the 30 seconds it took that 17-year-old to say that. The word ‘incomplete’ haunts me still. I’m convinced it’s a clue to all the uncertainties of adolescence. Adolescents feel, deep in their evolutionary conscience, that something essential is missing.

As a parent and a teacher there is no age group that fascinates me as much as adolescents: that restless, ever questioning, bombastic but extremely vulnerable energy that never stands still long enough for us to define! In years gone by every tribe or small community was ultra dependent on this bloody-minded energy for its survival. Adolescents played an essential role in those societies doing things that older, more sober-minded, adults would no longer do themselves. George Washington was appointed Surveyor general of the Dominion of Virginia on his 17~ birthday; the average age of Spitfire and Hurricane pilots in the Battle of Britain was 19 and a half, and more than half of those killed in the American Civil War were below the age of 20.

Nowadays we tend to speak not about adolescents, but about teenagers. Teenagers as a group only became obvious enough for inclusion in the Oxford English Dictionary in 1954. It’s a recent concept. Let me explain. In 1900 the average girl started to menstruate at about the age of 19. Now, with better food and health care, menstruation frequently starts shortly after a girl’s 10th birthday. In 1900, most boys were sufficiently well established in a job by the age of 20 that they could afford to marry and start a family. The gap between childhood and becoming a fully responsible adult was measured in months rather than years.

But not now, not in the year 2001.

In an attempt to continuously ‘professionalise’ adult employment we often argue that a young person should not go into work until he or she has both a university degree and some form of post university experience. Full-time jobs for many don’t start until 22,23 or 24. The gap between being a child and full adulthood has lengthened to nearly 15 years.

Teenagers are a by-product of contemporary society; a society so determined to get the most out of life now, that we no longer have the time or the inclination to provide adolescents with apprenticeships that will fit them for a more distant future. We don’t quite know what to do with teenagers any more; their energy so often goes to waste.

Frequently their ostentatious confidence antagonises the older generations, and they bore themselves with self-indulgence. They don’t have a role in society that is in any sense useful. They really do feel incomplete. And so do we, as we realise that we are no longer part of that interconnected world that was our ancestors’ way of transmitting the wisdom of the ages.

At one point in my career at MGS I was invited to give up teaching for a year and to travel around the world raising money from old boys to rebuild the school. To a 24-year-old this was an amazing opportunity. Injust over a year I met some 3000 ex-pupils of one of the most elite schools in England. I was amazed and disappointed, for many of these boys had not grown to be the men I had expected to meet. “At school, if we did as was expected of us, we shone,” explained one. “Somehow or other it was different at university. There we were left largely to work things out for ourselves, and that we were not so good at doing. I guess we were over-taught at school. We were too dependent on the teachers. It would have been better for me if I’d learnt more about working things out for myself.”