The Greenwich Meridian Trail is a long distance walk is the creation of Hilda and Graham Heap from Lewes which follows the line of the Prime Meridian. The trail was inaugurated in 2009 to coincide with the 125th anniversary of the Greenwich Meridian. The walk begins at Peacehaven in East Sussex and ends on the coast at Sand le Mere in East Yorkshire. The official route guide cites 273 miles as the distance while the attached route files show a distance of 290 miles from start to finish. Bearing in mind that five of the route file miles are across the waters of the Humber Estuary I have concluded a distance of 285 miles as being the most accurate. As for the route, going from south to north the walk sticks as closely to the Prime Meridian line as possible. This takes the walk through the counties of East and West Sussex, Surrey, Greater London, Essex, Hertfordshire, Cambridgeshire, Lincolnshire and East Yorshire.