What a thing of wonder a mobile phone is. Six ounces of metal, glass and plastic, fashioned into a sleek, shiny, precious object. At once, a gateway to other worlds - and a treacherous weapon in the hands of the unwary, the unwitting, the inept. The Cleverley family live a gilded life, little realising how precarious their privilege is, just one tweet away from disaster. George, the patriarch, is a stalwart of television interviewing, a 'national...