Why do the clocks change?
The clocks change to move summer daylight into the evening. Whether the practice still makes sense is genuinely contested — here is the evidence on health, road safety and energy, with both sides represented.
What is the point of changing the clocks?
Direct answer. The purpose is to make better use of natural daylight: by moving clocks forward in summer, the evening gets an extra hour of light that would otherwise fall in the early morning while most people sleep.
When BST was introduced in 1916 the main goal was saving coal and fuel in wartime. Today the arguments are more about lighter evenings for leisure, retail and road safety than about energy. The core trade-off has never changed: lighter evenings mean darker mornings, and vice versa.
Key fact: Changing the clocks does not create daylight — it moves an hour of it from morning to evening (or back again).
Health: what the evidence shows
Is changing the clocks bad for your health?
Direct answer. There is a small, real spike in heart attacks after the spring change, but it is much smaller than headlines suggest. A 2024 peer-reviewed meta-analysis found about a 4% rise in heart attacks after “spring forward”, and no significant change in autumn.
Individual hospital studies have reported far larger jumps — one widely quoted US study found roughly a 24% rise in heart attacks on the Monday after the spring change — but pooling many studies brings the true effect down to around 4%. A Finnish national study also found ischaemic strokes were about 8% more common in the two days after a clock change. The likely cause is short-term sleep and body-clock disruption.
Key fact: The best pooled evidence (2024 meta-analysis) puts the spring heart-attack rise at about 4% — real, but far below the 20%+ figures from single studies.
Road safety: a genuine disagreement
Would lighter evenings make the roads safer?
Direct answer. Road-safety campaigners argue yes; the most recent UK data analysis argues the current system is already slightly safer. Both positions are evidence-based, which is why the debate persists.
The Royal Society for the Prevention of Accidents (RoSPA) backs Single/Double Summer Time — GMT+1 in winter, GMT+2 in summer — citing modelling that suggests around 80 fewer deaths a year from lighter evenings. That figure comes from 1990s Transport Research Laboratory modelling. However, a 2022 study in BMJ Open analysing actual British casualty data found the existing twice-yearly changes already produce a small net reduction in casualties — directly challenging the “abolish to save lives” case.
Key fact: RoSPA’s ~80-lives-saved figure is a 1990s model; a 2022 BMJ Open study of real GB data found the current changes already cut casualties slightly.
Energy & the abolition debate
Should the UK scrap daylight saving time?
Direct answer. It is a live debate with no settled answer. The original energy case is weak today, the health case is modest, and the country splits geographically — northern Scotland in particular loses out under permanent lighter evenings.
On energy, a US natural experiment in Indiana found daylight saving slightly increased electricity use, and a 2008 US government report found extended DST saved only ~0.03% of national electricity. On politics, the EU ran a 2018 consultation in which 84% of 4.6 million respondents backed abolition — though over two-thirds of replies came from Germany — and the European Parliament voted 410 to 192 in 2019 to end clock changes. That plan stalled in the EU Council and was never implemented. The UK’s own “Lighter Later” campaign and a Daylight Saving Bill in 2010–12 failed in Parliament.
Key fact: The EU voted to end clock changes in 2019 but it stalled and never took effect; the UK, now outside the EU, keeps the change under the Summer Time Order 2002.
Bottom line: Both the EU clock-change abolition and the US “Sunshine Protection Act” remain stalled in their respective legislatures. Barring new law, the UK’s last-Sunday rule is expected to continue throughout 2026–2031.
FAQ
Why do the clocks change in the UK?
To shift an hour of daylight from the early morning, when most people are asleep, to the evening, when they are awake to use it. The practice began in 1916 to save fuel and has continued, with breaks and changes, ever since.
Does changing the clocks save energy?
The evidence is weak and mixed. A US natural experiment in Indiana found daylight saving slightly increased household electricity use, and a US government report found extended DST saved only about 0.03% of national electricity. Modern lighting and heating make the original fuel-saving case far less clear-cut than in 1916.
Is the UK going to stop changing the clocks?
There is no UK law in progress to abolish the change. The EU voted in 2019 to end mandatory clock changes but the plan stalled and was never implemented, and the UK has since left the EU. For now the twice-yearly change continues under the Summer Time Order 2002.
Sources & further reading
We cite primary and authoritative sources. Time-zone rules can change when governments amend the law — always confirm critical timing with an official source.