The Seven Years' War began in 1756 and the government immediately gave orders for the defence of the dockyard; by 1758 the Chatham Lines of Defence were built. Over a mile long, they stretched across the neck of the dockyard peninsula, from Chatham Reach, south of the dockyard, across to Gillingham Reach on the opposite side. One of the redoubts on the Lines was at Amherst. The batteries faced away from the dockyard itself to forestall an attack from the landward side; the ships and shore-mounted guns on the river were considered sufficient to protect from that side. The lines of defence are now part of the Great Lines Heritage Park and also the Lower Lines Park (near MidKent College, Gillingham Campus).