The national mapping agency in the United Kingdom, which publishes general and specialized maps of the country at several scales. The OS began in 1791, when the British government, fearing invasion following the French Revolution, instructed its board of ordnance (equivalent to a defence ministry) to survey and map the south coast of England. That operation led to the surveying and mapping of the entire country. While remaining a government agency, since 1999 the OS has had the status of a ‘trading fund’, which gives it greater responsibility for its own finances and planning, and more freedom to develop new initiatives.