In this Christmas special, Gregg Wallace, Cherry Healey and Ruth Goodman explore the fascinating factory processes and surprising history behind our favourite festive treats.Gregg follows 24 hours of production at the world's largest mince pie factory, where they will make 180 million mince pies this year. As he helps to mix pastry and stew mince, Gregg discovers the challenges of producing 2,000 perfect pies every minute. He also attempts to roll the sponge on the Yule log conveyor belt - with disastrous results.Cherry travels to south Wales to meet the workers who make enough tinsel in a year to reach Hawaii, and she is given special access to a high-tech factory that produces over 400 million metres of bestselling wrapping paper.Meanwhile, Ruth Goodman discovers the explosive history of Christmas crackers.