Sunday Feature: Alexandra Harris presents a cultural history of the cold. With the help of writers including Simon Armitage, A.S. Byatt, Katherine Swift and Adam Gopnik Alex looks at the way our literature began with work mesmerised by the beauty and horror of cold. In Yorkshire Simon Armitage discusses Sir Gawain and the Green Knight imagining the Pennines crossed by Gawain, hung with icicles on his hunt for the Green Knight. And Katherine Swift takes us on a winter tour of her garden in Shropshire.