About London time
London sits on Greenwich Mean Time — the historic prime meridian at the Royal Observatory in Greenwich is literally where the world’s time coordinates begin.
London is the reference point for UTC itself, so “GMT” and “London time” are used almost interchangeably — though for half the year the city is actually on BST (UTC+1). The Royal Observatory’s red time ball still drops at 13:00 daily, a Victorian habit that let ships on the Thames set their chronometers. Global markets often quote schedules in “London time,” which trips people up during the two-week gaps around U.S. and EU clock changes.
Greenwich prime meridianBig Ben chimesLondon Stock Exchange hours