In his Presidential Address, presented at the Annual General Meeting of the Institute held in London on 19 October 1977, Sir Edward Fennessy, until recently Managing Director Telecommunications at the Post Office, traces the role of navigation in the development of ocean cable laying from the earliest days. Today, telephone cables capable of bearing several thousand telephone conversations link the continents; plans are now well advanced for the laying of a cable between Cornwall and the United States which will provide some four thousand circuits. To lay and maintain these cables calls for all the precision obtainable from the most modern electronic aids to navigation and position fixing, including the satellites.