Clock changes: is it time for change? Contents

Chapter 4: Ending clock changes in the UK

100.Even if the UK were not obliged to abolish seasonal changes of time, any future Government could decide to do so, either unilaterally or after weighing the consequences of its EU neighbours doing so. This chapter considers what such a change might mean for different economic sectors and how the implementation of either permanent winter-time or summer-time might affect different industries and parts of the UK.

Implications of abolishing clock changes


101.As we explained in Chapter 2, abolishing clock changes would impose an onerous rescheduling exercise on airlines operating to, from and within Europe (see paragraphs 54 and 55). Mr Ireland of IATA felt that the UK aviation sector would be no exception, given the congestion at UK airports and legal constraints such as night restrictions.119 While he was concerned that the abolition of clock changes would be “a bit of disaster” for the UK aviation industry,120 the complexity of the issues was such that he found it impossible to provide an estimate of costs. He told us that an estimate could be produced by involving “co-ordination organisations in Europe and the UK”, but even then, “we would still be guessing what other capacity inputs and factors had an impact on those decisions”.121

Gas and electricity markets

102.Ofgem told us that, if clock changes were discontinued, “multiple components” of Great Britain’s market governance framework would need updating, possibly through both “legislative changes” and “changes to the industry licences and codes”. There would be “an initial administrative cost”, but operators in both the gas and electricity sectors had “well established procedures” for managing changes to time arrangements. Ofgem suggested that, beyond the initial implementation effort, the abolition of clock changes could benefit the energy and gas sectors, through “simplifying market rules and operations”.122

103.A similar view was taken by ELEXON, which administers the Balancing and Settlement Code (BSC) for the electricity sector in Great Britain: “Discontinuing [seasonal changes of time] would reduce some of the complexity and risk associated with the two clock change days.” ELEXON told us that, from an industry perspective, abolishing clock changes would require a “co-ordinated industry implementation project”, involving “central BSC systems, industry market participants (such as suppliers and generators), power exchanges and organisations that either trade over or operate an electricity interconnector” with an EU Member State.123


104.The National Physical Laboratory (NPL), which is responsible for the UK’s measurement systems, told us that abolishing seasonal changes of time would have no implications for precise time-keeping in the UK, which is based on UTC and relies on “continuously-running commercial atomic clocks”. Adjustments would, however, be required to the UK’s national radio time signal, MSF:

“The signal carries a time code that provides the current UK civil time, taking into account the existing seasonal time changes … If the proposal to end seasonal time changes is adopted in the UK, the service can be configured to disseminate the new form of UK civil time and the large number of clocks in the UK synchronised to the signal should continue to operate correctly.”124

105.Referring to computer-based clocks, IANA stated that “it would not be much of a problem to accommodate the abolition of twice-yearly clock changes”, provided there was a sufficient lead-in time.125 Mr Skeet, a software engineer, explained that updating devices’ time information would involve several steps and actors, including IANA, operating system maintainers, and end users.126

106.IANA made several suggestions about how to facilitate the transition to a year-round time zone for application developers:

107.The abolition of seasonal changes of time in the UK in any circumstances would require adjustments in a range of sectors, from transport to energy and software development. Such adjustments would bring some transition costs, which could be burdensome for industries where scheduling, especially internationally, is of concern, such as aviation. We received, however, no estimate of the potential size of these transition costs for any industry, or for the economy as a whole.

The choice between winter-time or summer-time

108.Several witnesses engaged with the question of whether it would be more beneficial for the UK to adopt permanent winter-time or summer-time. Although this was outside the scope of our inquiry, we summarise their views below as an illustration of the competing interests that would be involved.

The case for permanent summer-time

Road safety

109.RoSPA, a road-safety charity that has long campaigned for lighter evenings, told us that a move to permanent summer-time “could save an estimated 30 lives [annually] by providing an extra hour of usable daylight during the autumn and winter”. RoSPA reasoned that the number of road accidents generally peaks in the afternoon, owing to greater driver fatigue and longer journey times for drivers and pedestrians. In addition: “Every autumn when the clocks go back and sunset occurs earlier in the day, road casualties rise”.128

110.RoSPA backed its argument with road accident figures from the 1968–71 British Standard Time experiment, showing that during the experiment casualties fell by 11% in England and Wales and 17% in Scotland. RoSPA cautioned, however, that the “experiment coincided with the introduction of road side breath tests and the 70mph speed limit”,129 and we note also that other potential confounding factors exists, such as the overall amount of daylight in the winter and seasonal changes in weather, which need to be accounted for in a systematic way.130 Nick Lloyd, Head of Road Safety, RoSPA, drew attention to a 2018 study by the RAC Foundation and Road Safety Analysis, which indicated that, between 2012 and 2017, there were “204 more personal injury collisions per year over the two fortnightly periods when the clock changes took place”. He was unable to identify any evidence from other countries in the same latitude as the UK, but believed that similar conclusions would also be drawn in countries such as Germany or France.131


111.UKTPO held that permanent summer-time would be preferable from a trade perspective, minimising time differences between the UK and EU countries.132

112.A4E and Mr Ireland agreed that adopting permanent summer-time could mitigate the impacts on the aviation industry, not least because the IATA summer-season—coinciding with summer-time in the EU—was “10 weeks longer than the winter season” and fell “when demand [wa]s highest”.133 Mr Ireland suggested that the adoption of permanent winter-time would have longer-term repercussions for long-haul services. He focused on flights from North America landing in Heathrow between 6 am and 7 am, telling us that while rescheduling them to a later time would prove difficult due to high congestion levels, bringing them forward might be difficult because of restrictions on night-flights, or simply unprofitable.134

The case for permanent winter-time

113.Except for ELEXON, which would find a move to year-round GMT “marginally easier” for technical reasons,135 witnesses based their case for permanent winter-time not so much on its benefits as on the expected drawbacks of permanent summer-time, particularly for northern parts of the UK.

114.The Scottish Government noted that “if clocks were not to be turned back an hour in winter, Scotland would have no daylight between 8 am and 9 am”. It expressed alarm that this would expose children going to school to greater dangers from traffic.136 Similar concerns about the impact on Scotland were voiced by NFUS.137 Mr Lloyd agreed that the perception that darker winter mornings would reduce road safety was widespread “among the general public, certainly in Scotland”, though he believed it stemmed from “misinformation”.138


115.NFUS warned that, despite the modernisation of farming practices, carrying out farm work in the dark remained “inherently more dangerous than doing it during daylight”. Nor would adjustments to existing work practices be always possible: “For example, gathering livestock in the morning to go to the market for opening cannot always be delayed”. 139 UFU concurred that permanent summer-time “would be deemed incompatible with the needs” of farmers.140 The National Farmers’ Union (NFU), however, held that “whether an extra hour’s daylight would be more beneficial in the morning or the evening depends on [the] individual farm and farmer”.141

Other factors

116.Ofgem did not take a view on which permanent time zone might be preferable from the perspective of gas and electricity markets. It recommended, however, that developments in the technology (for example, solar) connected to Great Britain’s energy system and its “operational patterns” should be considered in any future decision. It also made the point that adopting a permanent time zone might “shift demand” by moving “economic activity to periods of the day” with “more or less light”, or when it was “warmer or colder”.142 Dr Andrews told us that there was currently “no model” to quantify the economic implications of a shift in electricity demand patterns.143

117.Our short inquiry has highlighted the diversity of views on what time arrangements would best serve the UK, and the difficulty of choosing a permanent time zone, if the UK were to do so.

118.The benefits and drawbacks of permanent winter- or summer-time are likely to vary across sectors and regions and are not easily comparable or quantifiable. We recommend that any assessment of the two options should focus, as much as possible, on areas where it might be possible to collect hard evidence—for example, the costs to the aviation sector.

119.Road safety is a conspicuous example of how, even within one sector, there are conflicting views on the relative benefits of permanent winter- or summer-time. We note that some of the evidence cited by witnesses was several decades old and difficult to use to draw conclusions about seasonal changes of time given other confounding factors, such as the introduction of speed limits. We note also that, at least in the evidence we received, it was not wholly clear how “accidents” were being defined in statistics regarding road safety and changes of time.

120.We recommend that the Government look widely to all existing sources of evidence, seeking in particular studies relating to countries in a similar geographical position as the UK, including studies in the Nordic countries, and compile clear figures relating to road safety in the periods after the clock changes occur, to help identify the right course of action if clock changes are to be abolished.

119 Q 14 (Philip Ireland)

120 Q 11 (Philip Ireland)

121 Q 15 (Philip Ireland)

122 Written evidence from Ofgem (SCT0018)

123 Written evidence from ELEXON (SCT0014)

124 Written evidence from the National Physical Laboratory (SCT0005)

125 Written evidence from the Internet Assigned Numbers Authority (SCT0004)

126 Written evidence from Jonathan Skeet (SCT0021)

127 Written evidence from the Internet Assigned Numbers Authority (SCT0004)

128 Written evidence from the Royal Society for the Prevention of Accidents (SCT0006)

129 Ibid.

130 Q 17 (Nick Lloyd)

131 11 (Nick Lloyd)

132 Written evidence from UK Trade Policy Observatory (SCT0015)

133 Written evidence from Airlines for Europe (SCT0016)

134 Q 11 (Philip Ireland)

135 Written evidence from ELEXON (SCT0014)

136 Written evidence from the Scottish Government (SCT0019)

137 Written evidence from the National Farmers’ Union Scotland (SCT0028)

138 Q 12 (Nick Lloyd)

139 Written evidence from the National Farmers’ Union Scotland (SCT0028)

140 Written evidence from the Ulster Farmers Union (SCT0017)

141 Written evidence from the National Farmers’ Union (SCT0003)

142 Ibid.

143 Q 14 (Dr Justin Andrews)

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