Fancy dress may be inherently unfashionable but it has found a home in the seasonal wardrobe of many people the world over – the British in particular – in the form of the Christmas sweater. On 14 December, Save the Children encourage mass festive sweater wearing to raise awareness and funds for their charitable work. If you’re going to take part, listen in: Funny and fearsome, the Christmas sweater is a curious example of fancy dress becoming mainstream (albeit briefly) and in this short ‘bonus’ episode, Lucy and Ben consider its origins, implications and, mercifully, guide you through ‘dos’ and absolute ‘do nots’ of this modern festive tradition.