Double British Summer Time

Justin Madders Excerpts

Thursday 27th March 2025 Commons Chamber

[The Parliamentary Under-Secretary of State for Business and Trade (Justin Madders)]

I thank my hon. Friend the Member for Dunstable and Leighton Buzzard (Alex Mayer) for securing this debate. I am grateful for her insights and remarks on this important topic, which, as she explained, impacts on everyone’s lives in one way or another. She described the clocks changing as a bit of a faff, which I think we can all appreciate. She then went on to discuss the reasons she advocates for this change in great detail. In my remarks, I will go on to explain why there are also potential negatives to what is being proposed.

As my hon. Friend mentioned, seasonal clock changes were first proposed in the early 1900s to extend daylight hours for recreation, to improve health and to save on lighting costs. At the time, clocks were set to Greenwich mean time all year round, resulting in early sunrises and sunsets in the summer. The idea gained traction during the first world war because of the need to conserve coal, which led to the adoption of changes in 1916. Biannual clock changes have continued ever since, with a brief deviation from the pattern during the second world war, when double British summer time was introduced, and between 1968 and 1972, when the clocks were put forward but not back as part of an experiment. I think those were also the first four years of my parents’ marriage, an experiment that thankfully has lasted much longer. It was eventually discontinued, however, due to inconclusive results regarding its effect on road casualties.

About 70 countries worldwide currently adopt some form of daylight saving. British summer time is the UK’s version of European summer time, which follows the same pattern by changing the clocks twice a year by one hour. This synchronisation allows for smooth transactions in trade, travel and communication across Europe.

The Government are aware that the issue of daylight saving has, at times, attracted extensive public and political debate, with suggestions to adopt British double summer time. British double summer time was introduced for a short period during the second world war, as I have mentioned. By extending daylight hours into the evening, it reduced the need for artificial lighting, thereby conserving fuel. Introducing British double summer time would result in clocks remaining one hour ahead of Greenwich mean time in the winter and moving two hours ahead in the summer.

By observing British summer time, the UK maintains a one-hour difference with European countries throughout the year. This would not be the case under British double summer time. Using Germany as an example, the time difference with it would vary between winter and summer. In winter, both the UK and Germany would be one hour ahead of GMT, resulting in no time difference. During summer, the UK would be one hour ahead of Germany.

The Government believe that the current daylight saving arrangements represent the optimal use of the available daylight across the UK. Changing the current arrangements would impact all citizens in the UK and Northern Ireland and would require public consultation and assessment of the impact on businesses across all sectors of the economy.

As my hon. Friend has mentioned, there would of course be benefits to moving to double British summer time. We know that darker hours exacerbate mental health conditions, particularly seasonal affective disorder. The shorter days and reduced natural daylight, as a result of clock changes, can worsen symptoms according to the charity Change Mental Health.

We also know that there is evidence that enforced clock changes can disrupt sleep health, especially in a forward direction such as that which currently occurs in March—and will be happening again in three days’ time. However, we also know from the British Sleep Society that natural daylight in the morning is critical for alignment of our internal body clocks. Moving to double British summer time would cause darker mornings, especially in winter.

We are also aware of some evidence that abolishing clock changes would reduce road accidents. Analysis from the RAC Foundation and Road Safety Analysis shows that between 2012 and 2017 there was a 2% increase in road accidents over the two fortnightly periods when the clock changes took place. In terms of energy use, keeping to GMT plus 1 during the winter months might be expected to reduce overall energy use, as people use less artificial light in the evenings. However, the effects are likely to be small in magnitude, and may even be uncertain—there might be no effect at all.

The most significant effects are likely to be associated with lighting demand as demand switches from the evening to the morning. While there might be some benefits, there would be a risk of the UK energy system being affected by the time zone choices of neighbouring countries with which it trades gas and electricity. For example, the time difference between the UK and France means that peak demand is staggered across the two countries and allows for interconnectors to play a role in meeting peak demand throughout the year. This results in lower energy generation required in Great Britain and lower prices for consumers. If the time difference were to change, that could have impacts across the energy system, including on the benefits assumed from interconnection.

There might also be road safety impacts. Advancing the clock in spring creates a short-term disruption in sleeping patterns, which can cause fatigue. This can lead to inattention, poor decision making and delayed reaction times, all of which are contributing factors to road traffic accidents. Summer time arrangements have led to concerns about the disrupted biorhythms of animals, with respect to changing milking and feeding schedules, although of course these impacts are expected to be reduced due to the deployment of new equipment, artificial lighting and automated technologies.

The approach to daylight saving is a complex area, given the importance of just-in-time supply chains to many industries. Many sectors and businesses, example in the aviation industry, would need considerable notice of any such change.

There have been examinations of all this in the past. Following a call for evidence, the House of Lords report “Clock changes: is it time for change?” found that the abolition of seasonal changes of time in the UK in any circumstances would require adjustments in sectors ranging from transport to energy and software development. Such adjustments would bring some transition costs, which could be burdensome for industries when scheduling, especially internationally, which would be a concern, particularly for aviation. In that report, the European Union Committee concluded that it did not receive compelling evidence to suggest that the current system of seasonal changes is problematic for the UK, while noting that there is a lack of contemporary studies on the subject.

Moving to double British summer time would create a time border between Ireland and Northern Ireland, if Ireland maintained its current approach to time. That non-alignment could cause problems for transport, particularly aviation, tourism, trade and business in general, with higher impacts if there was only a part-year alignment. This view is not only held by UK industries and representing bodies; it was also reported in EU and non-EU countries’ responses to a 2018 European Commission consultation.

In the UK, seasonal changes of time facilitate lighter evenings for over half the year and reduce morning darkness in winter. The latter effect is particularly pronounced in northern parts of the UK, especially Scotland. Double British summer time in the north of Scotland would mean no daylight in the winter before 10 am, while in the rest of Scotland sunrise would be at 9 am. Opponents of change point out that in Scotland children would have to travel to and from school in darkness. As pointed out by the Scottish Government in their written evidence to the Lords Committee, farm vehicles and other large vehicles would spend more time on the roads during the hours of darkness, further adding to the risks.

In 2012 the Department for Business, Innovation and Skills published a review of the scope, quality and robustness of available evidence regarding clock changes. The review found that there are challenges in looking at the overall picture of the impacts that might occur across a range of issues, including energy consumption and road traffic accidents.

To conclude, this Government will always listen carefully to any arguments that are put forward around how to mitigate challenges and provide support, particularly in areas such as mental health. We appreciate the concerns raised about the potential impact of clock changes on mental health and road safety, and we will always welcome views on how we can enhance our existing measures and initiatives.

As set out in our “Get Britain Working” White Paper, the Government are committed to expanding access to NHS talking therapies for adults with common mental health conditions such as depression, including seasonal affective disorder. This Government treat road safety with the utmost seriousness, and we are committed to reducing the numbers of those killed and injured on our roads. My ministerial colleagues at the Department for Transport are developing the first road safety strategy in over a decade, and will set out more details in due course.

I thank my hon. Friend the Member for Dunstable and Leighton Buzzard again for securing the debate. She has raised some interesting points, but the evidence for the case for change is not overwhelming. However, I will take this opportunity to remind everyone that the clocks go forward on Sunday, and it is also Mother’s Day.

Question put and agreed to.