Numerous east-west routes in Leicestershire continue into Lincolnshire and on to the Norfolk coast. They have been used to transport salt from the coast, wool to the coast and by pilgrims going to and from Walsingham. And, most likely, were created by Neolithic farmers. The clues are mostly in minor place-names.
update: since this video was uploaded Stuart Evans has written about 'The Iron Age Landscape of the Salt Way'. See lahs.org.uk/blog/the-iron-age...