Wade through the dirty underwear, discarded magazines and half-eaten sandwiches and you find yourself in the heart of the teenager’s lair. Despite first impressions, this is a high-tech space, bristling with the latest gadgetry. You may call it a bedroom, but to its owner it is an arcade, complete with computer, TV, games console, CD player and other electronic toys. No wonder teenagers stay up till the small hours, then have to be prised from their beds in the morning, only to fall asleep during double history. They are their own worst enemies, willing victims of our 24-hour society.

Or are they? It is comforting to think that teenagers are sleepwalking through their lives by choice, because at least that means we should be able to persuade them to lay down their games consoles and go to bed. But if that is the case, how come their peers in the developing world, in areas that lack basic electricity let alone PlayStations, still stay up late into the night? Is it possible that teenagers just cannot get to sleep earlier? Evidence is emerging to suggest that is indeed the case: teenagers are biologically incapable of going to bed at a sensible time.

This is no trivial matter. If teens are refugees from a different biological time zone, then by making them get up and go to school before their bodies are ready we are not just making school life difficult for them and their teachers, we are also putting them at risk. Sleep deprivation jeopardises their future prospects, their health and even their lives. What’s to be done about it?

Being a teenager is a tiring business. Though experts recommend that adolescents get at least 9 hours sleep a night, only 1 in 5 get that amount, with many saying that they have less than 7 hours on school nights. If late nights are bad for British and Australian teens who have to be in class at 9 am next morning, they have got to be worse for youth in the US, where schools start as early as 7 am, and in much of continental Europe where an 8 am start is the norm. No wonder the most recent survey, published by the US National Sleep Foundation in March, found that more than a quarter of 11 to 17-year-olds fall asleep in class at least once a week, and that over 50 per cent say they do not get enough sleep and feel tired during the day.

So why don’t teenagers just turn out the lights, go to bed and get a good night’s sleep? It’s now looking as though they just can’t.

It has long been clear that different individuals can have markedly different sleep patterns. Most of us display some degree of “morningness” or “eveningness”: we are either “larks” or “owls”. This is largely a matter of genetics. Natural early risers are born that way, and so are people who prefer to get up late and stay up deep into the night.