The Royal Observatory's public clock, the Shepherd Gate Clock, set permanently to Greenwich Mean Time ©NMM. Repro ID: D5601Please note: This exhibition has now closed

See our feature on British Summer Time, based on the exhibition.

2007 marked 100 years since British Summer Time was first proposed. Changing the clocks for summer time is now an annual ritual in Britain and countries around the world. But why change the clocks, which way should they go, and whose idea was it in the first place?

This free special exhibition at the Royal Observatory ran from 23 March 2007 until the end of October to coincide with the changing of the clocks.