This Sunday, October 28, clocks will go back an hour at 2am, returning UK time to Greenwich Mean Time (GMT). Clock times have been biannually tweaked twice a year since 1916, following the Summer Time Act, with the exception a few years during World War 2. Britain was two hours ahead of GMT in the summers of 1941 to 1945, while running on British Double Summer Time.
This occurred as the clocks were not returned by an hour at the end of summer 1940.
In the succeeding years, clocks are advanced by an hour in spring and held back by an hour each autumn.
Daylight saving time is designed to make better use of the light.
When clocks are moved backward an hour in the autumn, it transfers an hour of daylight from evening to morning, when it is considered more useful.
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What are the consequences of Daylight Saving Time (DST?
DST has wider ramifications than enjoying an hour extra in bed, such as energy use, farming and even mood.
Some think DST actually does not save energy, as less household usage in the evenings in summer you;d be offset by greater morning usage.
Health impacts, such as additional exposure to sunlight through the summer DST months, boosting their vitamin D levels have been mooted.
Critics, however, argue disruption to sleep patterns can impact negatively on human health.
Some studies even indicate the risk of having a heart attack increases in the first three weekdays after switching to DST in the spring.
However, they also found the extra hour of sleep after the clocks went back in autumn decreased the risk of heart attacks in the first few weekdays after switching.