What would happen if the UK signed up to an extra hour of daylight in the evening?
Tourism: A £3bn boost
Tourism would reap some of the biggest benefits from putting the clocks forward two hours in the summer. A study by the Policy Studies Institute two years ago concluded that extra daylight in the evenings would boost tourism spending by £2.5bn to £3.5bn a year and create 60,000 to 80,000 new jobs. It is not so much the extra daylight in the long summer evenings that would make the difference but the extra daylight in the spring and autumn.
With sunset taking longer to draw in, many attractions that have closing times dictated by dusk could stay open later. The calculation that earnings would increase by 3 to 4 per cent takes into account the factor that "there is far more tourist activity after lunch compared with the morning". The report concluded: "There can be little doubt that the clock change would boost tourist activity and earnings. It is certain that the extra hour would result in far more outdoor sports, tourism, day trips, weekend breaks and so on."
Lady Cobham, chairman of VisitEngland, added: "Longer, lighter evenings do lift the spirits and if we can encourage more people to get out and about experiencing all that this country has to offer, then that can only be a good thing."
Safety: Dozens of lives saved
Improvements in road safety are pushed as one of the strongest arguments for adopting the Single Double Summer Time system.
Research done on behalf of the Department for Transport has suggested that the extra daylight later in the day will each year save around 80 lives and prevent more than 200 serious injuries.
The figures are based on studies of 1968 to 1971 when Britain remained one hour ahead of Greenwich Mean Time. It was the same as British Summer Time, but as it carried on through the winter it was called British Standard Time.
One of the reasons fewer accidents are thought to take place on dark mornings compared to driving home on dark evenings is because of the distance of journeys. In the morning people tend to drive straight to where they need to go – work, perhaps via school to drop off children. But in the afternoon and evening, when they may be tired, they are more likely to detour for tasks such as shopping or visiting friends which increases the distances travelled and heightens the chances of an accident.
The Royal Society for the Prevention of Accidents believes changing the time is the second most effective measure that could be taken to improve road safety, after cutting drink-drive alcohol limits.
Farmers: Working in the dark
Keeping an hour ahead of Greenwich Mean Time during the winter months could be a serious inconvenience, and perhaps even a danger, to farmers, who are among the principal opponents of any change.
The National Farmers' Union Scotland (NFUS), where winter daylight is in even shorter supply than in England, is particularly concerned at the prospect of an hour's extra darkness in the mornings.
Farmers often have to move heavy agricultural machinery in the mornings in readiness for the day ahead and the union is concerned at the potential dangers of moving them around in darkness.
Similarly, many livestock farmers like to make feeding their animals the first task of the day, but this could be hampered by the lack of light.
It might be possible to alter the hours of work in farms, but the union is worried that workers will expect to be paid more if they change from the usual 9 to 5 to, say, 11 to 7.
Wendy Irwin, of NFUS, said: "The reality is that the work has to be done no matter what the hours are. I'm quite sure farmers would adapt if they had to but it's easier for them if it stays the way it is."
The environment: Lower emissions
Climate-change activists are calling for the clocks to go forward because of anticipated reductions in carbon dioxide emissions.
If people live more of their lives in daylight, they argue, they will use the lights less in their homes and businesses.
Britain is still heavily dependent on power plants that use fossil fuels, and huge quantities of CO2 are released into the atmosphere when coal, oil or gas are burnt.
It is calculated that if Britain was to put the clocks forward again it would be able to reduce its CO2 emissions by 450,000 tonnes every year, the equivalent of removing 185,000 cars from the roads. It would only be a fraction of the 568 million tonnes emitted by Britain every year, but it would be painless way to cut emissions.
Franny Armstrong, a climate activist involved in the Lighter Later campaign organised by the 10:10 group, said: "Hands up who doesn't want our country to be safer, lighter, more prosperous and with less pollution? And who doesn't want to save money on their electricity bills without lifting a finger?"
Education: A safer school run
Every time there is a suggestion that sunrise should be delayed by an hour in the winter, there are warnings that it will increase dangers for children.
The problem is particularly acute in Scotland, where in the winter, being an hour ahead of GMT would necessitate many more children journeying to school in darkness. They already have to travel home in the dark for much of the winter.
In mainland Scotland it is almost 9am before the sun rises on the shortest days of the year, and on some of the more northerly islands, such as the Shetlands, it can be even later than this. A change to the clocks would mean most children in Scotland could watch the sun rise while they were in the classroom.
Nevertheless there are some who believe that despite the sun rising later, journeys to school will be safer than they are today because of a reduction in road traffic accidents.
Tom Mullarkey, the chief executive of the Royal Society for the Prevention of Accidents, suggested that rush-hour accidents would be likely to fall by 17 per cent in Scotland, an even bigger reduction than the 11 per cent expected in England and Wales. "Scots will gain even more than the English on this," he said.
The City: A lie-in for traders
By living an hour ahead of today's time, businesses would come into line with European working hours, allowing them to open their doors at the same time and leave for home in unison.
Markets in the City are already forced to open early so as to start at the same time as their European rivals. While it means people working in the London markets have to start earlier than most other commuters, to delay the opening time would risk missing out on huge money-making opportunities over their European rivals.
Alignment with Central European Time, which covers virtually all of mainland Europe, would allow the British markets to open simultaneously without the staff having to rise earlier than their counterparts on the continent.
Business leaders might also find life easier. The hour's difference between British and European clocks means companies separated by the English Channel lose two hours of potential business each day – the Continentals start an hour before the British who leave an hour later in the day. It should also mean that businesspeople with morning meetings in places like Brussels or Paris would have a better chance of travelling there on the same day instead of paying for an overnight stay.
Children: Bedtime resistance
Getting a child to bed can be one of the most trying tasks of the day for a weary parent. "But I'm not tired!" is a cry echoed in virtually every family.
Having to drag/order/cajole a child to bed when it is still sunny outside, especially when the noise of other children playing can still be heard through the open window, can be rather more traumatic. With Single Double Summer Time the difficulties will only get worse with the number of days when the sun goes to bed before the child rising significantly.
But for parents whose children wake up with the light rather than the clock, however, there could be the benefit of an extra hour in bed on a weekend morning.
Scotland: Land of midnight sun
Parts of Scotland would come within touching distance of entering the realms of the midnight sun should the clocks be altered to be two hours ahead of GMT during the summer.
The sun already sets after 10.30pm on the longest of the summer nights in Lerwick on the Shetlands, and with the clocks pushed forward further sunset would be delayed until past 11.30pm.
The Scottish mainland wouldn't be far behind with sunset just short of 11.10pm after close to 18 hours of sunshine on a well-behaved summer's day. England and Wales would lag some way behind with sunset in the far south at about 10.30pm. But they would maintain their winter advantage of slightly more daylight.
A brief history of time
The idea of changing the clocks to make the most of daylight hours was first suggested seriously in 1895 by George Hudson, a New Zealand entomologist. William Willett, an English builder, came to a similar conclusion independently in 1905 after noticing how many shutters in London were closed to the morning sunshine during summer. In 1907 he wrote a pamphlet proposing British Summer Time (BST), and a year later a bill was presented to Parliament, though it failed to win enough support.
Daylight Saving Time was first introduced by Germany during the First World War in 1916 as a means of saving coal stocks. Britain followed in 1917, to widespread protest. BST was continued until the Second World War when the British Double Summer Time (BDST) system was adopted because of the need to burn less fuel.
After a brief experiment with GMT, Britain returned to BST until 1968 when a three-year test was carried out to assess being an hour ahead of GMT all year round – this became British Standard Time. BST was reasserted by the Summer Time Act 1972 and despite numerous efforts to enforce change, it has remained largely unaltered since.