It was the school holidays and there were lots of teenagers in my local park. I sometimes spot them meandering home, but I rarely see them en masse as it were. Blind to the bluebells, peacocks and glories of nature all around us, they were glued to their palm-sized screens. What were they so engrossed in – some kind of game or trivial video, a map of the park perhaps, unnecessary given the proliferation of signs? Are they texting, e-mailing, or trawling through the Internet, or all of the above? If one did not know what these shiny seductive objects were, one might think that they controlled the person, rather than the other way round. And to a large degree they do.