So, this is Christmas. The magic of the festive season is, in many ways, all about its predictability. Even in disrupted times, we know that we'll get more time to ourselves, and with our friends and family (even if virtually), to focus on what really matters. And, just as reliably, the first herald of Christmas will be the world of media and marketing sprinkling a layer of snow over everything it does. The Christmas advert has, in fact, become something of a cultural tradition all of its own, especially in the UK, where the nation's big retailers now engage in a good-natured annual competition to produce the big-budget campaign which best captures the mood of the nation. From middle-class department store stalwart John Lewis to