<P> Originally, astronomers considered a GMT day to start at noon while for almost everyone else it started at midnight . To avoid confusion, the name Universal Time was introduced to denote GMT as counted from midnight . Astronomers preferred the old convention to simplify their observational data, so that each night was logged under a single calendar date . Today Universal Time usually refers to UTC or UT1 . </P> <P> The term "GMT" is especially used by bodies connected with the United Kingdom, such as the BBC World Service, the Royal Navy, the Met Office and others particularly in Arab countries, such as the Middle East Broadcasting Centre and OSN . It is a term commonly used in the United Kingdom and countries of the Commonwealth, including Australia, New Zealand, South Africa, India, Pakistan and Malaysia; and in many other countries of the eastern hemisphere . In some countries (Britain for example) Greenwich Mean Time is the legal time in the winter and the population uses the term . See GMT in legislation, below, for further explanation . </P> <P> As the United Kingdom grew into an advanced maritime nation, British mariners kept at least one chronometer on GMT to calculate their longitude from the Greenwich meridian, which was by convention considered to have longitude zero degrees, internationally adopted in the International Meridian Conference of 1884 . Synchronisation of the chronometer on GMT did not affect shipboard time, which was still solar time . But this practice, combined with mariners from other nations drawing from Nevil Maskelyne's method of lunar distances based on observations at Greenwich, led to GMT being used worldwide as a standard time independent of location . Most time zones were based upon GMT, as an offset of a number of hours (and possibly a half - hour) "ahead of GMT" or "behind GMT". </P> <P> Greenwich Mean Time was adopted across the island of Great Britain by the Railway Clearing House in 1847, and by almost all railway companies by the following year, from which the term "railway time" is derived . It was gradually adopted for other purposes, but a legal case in 1858 held "local mean time" to be the official time . On 14 May 1880, a letter signed by' Clerk to Justices' appeared in' The Times', stating that' Greenwich time is now kept almost throughout England, but it appears that Greenwich time is not legal time . For example, our polling booths were opened, say, at 8 13 and closed at 4 13 PM .' This was changed later in 1880, when Greenwich Mean Time was legally adopted throughout the island of Great Britain . GMT was adopted on the Isle of Man in 1883, Jersey in 1898 and Guernsey in 1913 . Ireland adopted GMT in 1916, supplanting Dublin Mean Time . Hourly time signals from Greenwich Observatory were first broadcast on 5 February 1924, rendering the time ball at the observatory redundant . </P>

Gmt is named after a place in which country