DO MOBILE telephones harm children? Sir William Stewart, of the National Radiological Protection Board, is not sure. He says that because of the potential health risks, children should use mobiles only when necessary — but insists that absolute proof is absent. Sir William is out of touch. Mobiles are gravely injurious to health. Whether they cause tumours is not instantly relevant. Their impact on physical wellbeing and efficient brain function is as luminous as their popularity with children is universal.

The very young may be safe. My three-year-old gets exercise and stimulation simply by lifting her huge, toy mobile phone. Her six-year-old sister ends the day exhausted after running multiple circuits of the house in pursuit of tweeting mobiles discarded by her older siblings’ friends. But the larger pair, a girl aged 14 and a boy of 12, are members of a generation already corrupted by mobiles and in danger of declining into absolute incapacity.

Adolescence was a bad time for communication before the advent of the mobile. Now there is no need for teenagers to talk at all. They need not abandon the television to grunt at their parents but text instead. Many calories that could be burnt by climbing and descending stairs are not expended at all. Even the infinitesimal energy required to type a message has been reduced by the use of two thumbs instead of ten fingers and the elimination of vowels.

When calls were announced from the family telephone the risky business of adolescence was never private. Now calls to potential boyfriends, girlfriends or drug dealers, which previous generations walked to telephone boxes to conduct, can be made from the bathroom. Any beneficial effect of sport is ruined when pizza is ordered from the changing rooms. Children need not even walk to a chemist to get pictures developed.

As for secondary harm, that modern prerequisite to treating a health threat seriously, in the case of the mobile telephone it is obvious. The impact on innocent adults is grim. Our mental health is imperilled by inane, polyphonic ring-tones. We face huge bills for fatuous communications that occur only because they can.

Sir William should get out of his laboratory. It is plain that mobiles render our children fat, lazy, sullen, static and stupid and, contrary to his suspicions, the risk increases with age until about the thirtieth birthday.