Daylight Saving Time.

21 maja 1916 roku Wielka Brytania po raz pierwszy wprowadziła czas letni, czyli DST - Daylight Saving Time.
Following Germany's lead, Britain passed an act on May 17, 1916, and Willett's scheme of adding 80 minutes, in four separate movements was put in operation on the following Sunday, May 21, 1916. There was a storm of opposition, confusion, and prejudice. The Royal Meteorological Society insisted that Greenwich time would still be used to measure tides. The parks belonging to the Office of Works and the London County Council decided to close at dusk, which meant that they would be open an extra hour in the evening. Kew Gardens, on the other hand, ignored the daylight saving scheme and decided to close by the clock.
Read more about the history of DST http://www.acurite.com/learn/clock-technology/daylight-saving-time-history-facts