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 treasure’ (his words), his wife Beverley, a celebrated novelist (although not as celebrated as she would like), and their children, Nelson, Elizabeth, Achilles, various degrees of catastrophe waiting to happen.