Why Britain remains locked in a century-old debate over shifting its clocks twice yearly.

Nature · Published 29 September 2026 Swipe more like this →

In short: British Summer Time shifts the nation one hour ahead of Greenwich Mean Time each spring, trading morning light for longer evenings. While the practice has persisted since 1916, it remains a lightning rod for controversy, pitting road safety advocates against those concerned about the impact on northern regions like Scotland.

The concept of British Summer Time originated with builder William Willett, who published his proposal in a 1907 pamphlet titled Waste of Daylight. Although Willett died in 1915, his idea was enacted by the Summer Time Act 1916. The system has seen radical departures, most notably during the Second World War, when Britain operated on British Double Summer Time, remaining two hours ahead of Greenwich Mean Time during the summer months from 1941 to 1945.

A significant experiment occurred between 1968 and 1971, when the government of Harold Wilson kept Britain on Greenwich Mean Time plus one hour throughout the year. While initial analysis suggested this saved roughly 2,700 lives on the roads during the first two winters, these figures were later modified downward. The experiment ended after a 1970 House of Commons vote of 366 to 81. Modern proposals, often termed Single/Double Summer Time, suggest applying this year-round shift to align the UK with Central European Time, potentially reducing CO2 emissions and road accidents.

Opposition remains fierce, particularly from residents in Scotland and Northern Ireland, where such changes could push winter sunrises to 10:00 or later. Legislative attempts to alter the status quo, such as the Daylight Saving Bill 2010–12, have repeatedly stalled in Parliament. As of September 2018, the UK government maintained it had no plans to end seasonal clock changes, leaving the nation to continue its century-old rhythm of adjusting to the sun.

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