The Port of London Authority has been managing a range of duties on the tidal Thames for more than 100 years. Their principal responsibility is the safety of navigation along 95 miles of river from Teddington Lock to the North Sea. They also promote the use of the tidal Thames, work to ensure security of port operations, and are responsible for protecting the marine environment. These books give the predicted height of the tide at every hour during the year, and are published separately for London Bridge, Tower Pier; North Woolwich; Tilbury; Coryton; Southend; Shivering Sands; Margate and Walton-on-the-Naze.