Marty Cooper, known as the "father of the cellphone" for his work in developing the first mobile phones at Motorola, recalls that he only became aware of the device's full potential as a result of actually using it. His secretary called him on his prototype mobile phone as he was getting into his car to drive to a meeting to say that it had been cancelled—thus saving him from a wasted journey. But explaining the benefits of being able to change plans on the fly to potential customers was difficult, he says, so the first phones were marketed instead on the basis that they could make people more productive, by allowing them to work while on the move. But today the idea of "approximeeting"—arranging to meet someone without making firm plans about time or place, and then finalising details via mobile phone while out and about—is commonplace.

The bus arrives in Trafalgar Square, and Mitchell is immediately impressed at how wirelessness has encouraged a more flexible use of the space. The large groups of teenagers we see on the square, he says, will have converged here by making shifting arrangements to meet via mobile phone — so-called approximeeting.

Loose arrangements can be made in the knowledge that they can be firmed up at a later stage; people can be forewarned about late or early arrivals; arrangements to meet can be progressively refined. But this kind of flexibility — we can call it approximeeting — can also engender a new sense of insecurity. Everything is virtual until the parties, the places and the moments come together to make it real. In this context the person without a phone becomes something of a liability.