The Royal Greenwich Observatory begins broadcasting the hourly time signals known as the Greenwich Time Signal.

The Royal Observatory, Greenwich is an observatory situated on a hill in Greenwich Park in south east London, overlooking the River Thames to the north. It played a major role in the history of astronomy and navigation, and because the Prime Meridian passed through it, it gave its name to Greenwich Mean Time, the precursor to today's Coordinated Universal Time (UTC). The ROG has the IAU observatory code of 000, the first in the list. ROG, the National Maritime Museum, the Queen's House and the clipper ship Cutty Sark are collectively designated Royal Museums Greenwich.

The Greenwich Time Signal (GTS), popularly known as the pips, is a series of six short tones broadcast at one-second intervals by many BBC Radio stations to mark the precise start of each hour. The pips were introduced in 1924, generated by the Royal Observatory, Greenwich, and from 1990 were generated by the BBC in London. The broadcast pips replaced an electrical time coordination system based on the railway telegraph network, which itself was an extension of the mechanical time balls in Portsmouth (1829) and later Greenwich (1833), which enabled navigators aboard ships moored in those places to set their chronometers for the determination of longitude on voyages.