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TURNING the clocks back each winter causes a surge in Britain’s greenhouse gas emissions and adds millions of pounds to power bills, according to a new study by Cambridge University engineers.
They found that darker evenings cause domestic consumers to use an extra 5% electricity, generating millions of tons of carbon dioxide (CO2 The report will be published this week, anticipating next weekend’s turning of the clocks back an hour from British Summer Time (BST) to Greenwich Mean Time (GMT).
It estimates that remaining on BST all year and perhaps renaming it Energy Saving Time could also prevent 104 deaths and 450 serious injuries on the roads each year by decreasing the amount of driving in the dark. The National Health Service would save £200m a year in treating injuries associated with daytime darkness.
Elizabeth Garnsey, author of the report and a reader in engineering and business at Cambridge’s Institute for Manufacturing, said: “Our current time policy costs us dearly in bills and emissions. CO2 “Setting the clocks back to GMT is an institutional practice so well entrenched it is exempt from evidence-based policy making. No systematic evidence has been produced and no research commissioned in support of the government’s position.”
Garnsey’s report adds a new twist to an argument that has lasted more than a century.
It has long been said that Britain would benefit economically from syn-chronising clocks with its European neighbours and that people would prefer to have more daylight in the afternoon and evening during the winter. However, such moves have been stymied by concerns over the impact on Scotland, where moving the clocks forward an hour would leave northern areas in darkness until about 9am.
The years 1968-71 saw an experiment in which Britain brought the clocks forward by an hour, but MPs voted to abandon it after anecdotal evidence of morning road accidents involving schoolchildren and disruption to dairy farmers and construction, delivery and postal workers.
Garnsey’s report says such anecdotes were misleading and were not backed by any formal attempt to gather evidence. Her new finding that putting the clocks back generates an extra surge in energy demand, carbon emissions and road accidents is likely to reopen the debate.
A significant factor in the energy surge is that, under GMT, around 35% of the population are asleep when the sun rises in winter and so make no use of the extra daylight. Then, because they arrive home from school or work in cold and darkness, they use more lighting and heating, causing a surge in demand, especially between 4pm and 6pm.
The costs and emissions are amplified because Britain can only meet these daily surges by switching on less efficient back-up generating plants such as oil-fired power stations. Such plants can take hours to heat up and cool down, pushing the costs and emissions of such power even higher.
Garnsey did not look at the impact on demand for gas consumption but believes it would show similar trends.
The energy-saving benefits of keeping clocks forward an hour were clear to wartime politicians. British Summer Time, also known as GMT+1, was created in 1916 to save coal. During the second world war, Britain used GMT+1 during the winter and GMT+2 in summer, again to reduce fuel consumption.
Britain might have moved permanently to such a regime in 1971 but MPs voted against after an emotive debate involving claims that putting the clocks forward had caused an increase in winter morning road accidents to schoolchildren. What they were not told was that this was more than offset by the much greater fall in accidents in the evenings.
Garnsey calculates that the 1971 decision has caused an extra 46m tons of CO2 to be released since then.
There are signs that senior politicians are ready for a rethink. A spokesman for Pat McFadden, the employment minister who also has responsibility for timekeeping, said he was reading the report “with interest”.
Tim Yeo, Tory chairman of the envi-ronmental audit select committee, who earlier this year tried to use a private member’s bill to bring the clocks forward by an hour in both winter and summer for a three-year experimental period, said: “The environ-mental case for action is unanswerable.”
There is, however, likely to be powerful resistance to any change from Scotland. Alex Salmond, the first minister, said: “The current system protects the safety of children travelling to school. Not putting the clocks back would leave Scotland in darkness until 8 or 9am.”
But Sylvia Thorne, an art teacher from Sanday in Orkney, said: “There isn’t much strength of opinion about it up here. The Scottish weather is so miserable in winter that it would make little difference.”

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Agreed changing the clocks is ridiculous but until someone comes up with the best arrangement it wil have to be as more accidents seem to happen in poor light and as a reader as already pointed out there is less traffic at 1500GMT/1400BST than in the morning rush hour.
Then what about the Scottish folk - they would be doomed to much darker mornings if we stayed on BST - I live in Essex so it is not so much a problem in the south.
How about put the clocks forward by half an hour and have a happy medium - would this solve anything?
An idea anyway.
MJarvis, basildon,
Personally I would rather have GMT all year round. Lighter mornings are much better than lighter evenings but I accept that everyone doesn't feel the same. At least the way we do things at present means that all of the people are happy for half the year. As regards accidents I can't accept that having BST in the winter will make very much difference. In the mornings children and adults would all be on the move at the same time - in the dark. It's a time when drivers are liable to be half asleep or rushing because they are going to be late for work and therefore more prone to accidents. In the afternoon/evening children come out of school much earlier than most adults leave work so they surely can't be at more risk than they are in the morning. I remember the experiment which took place some years ago and children had to be equipped with flourescent armbands etc. because of the increased risk of morning accidents.
C. Burton, Solihull, England
I personally do not get up that early and anywayI would only have my bedroom light and later perhaps the kitchen light on in the morning. In the evening with an evening meal to cook and wanting to sit and read or watch television instead of gardening I use many more lights during the evening "hour". My Scottish relatives think it's nonsense too. F B Somerset
Faith Elizabeth Brown, Shepton Mallet, UK
Changing the clocks twice a year is a ludicrous waste of time in the 24/7 21st century. Keeping to BST for the whole year would be the best balance for all groups throughout England. I have a strong internal body clock, so find the change difficult and stressful. This year I am blissfully serene - with no schoolchildren in the house any more I have simply left my clocks on BST, or as I call it 'Natural Time'. We have one radio-controlled clock in the house which has reset itself to 'Government Time', so my husband can ensure he doesn't get to work an hour early. I am angry that people will lose their lives because the Government insists on making schoolchildren walk home in the dark, but until they see sense and do the right thing, I, at least, am now happy. For anyone who thinks that having a different personal time zone to the Government time will cause problems, I can say having lived in a continent with several different time zones, that it really isn't a problem
J Cooper, Newcastle upon Tyne,
I don't care which time system we're on, as long as we don't have to spend an hour changing all the clocks, watches & various devices, every 6 months. What a palava!
Pete C, Birkenhead, UK
If Scotland still want the clocks to go back then let them go their own way. Here in Engand, I don't know anybody who thinks putting the clocks back is a good idea. Everybody would much rather have more light in the evening, than the morning. The environmental savings outlined about speak for themselves. Let's stop this frankly absurd tradition as soon as possible, and allow the vast majority of people to make the most of the daylight hours.
GP, Manchester,
The UK has enough problems with dull weather and grey wet skies. How could it get any worse, I know - let's set the clocks back in October to make it even more miserable. CHANGE THIS RIDICULOUS SYSTEM AND DO IT NOW. Scottish farmers can have an extra hour in bed in the winter, then get up early in summer. How difficult is that?
Stefano Ricci, London, UK
The safety of school children on their way to & from school is surely the most compelling argument to stay on British Summer time (GMT +1) for the winter.
Yes, there is only the same number of daylight hours, but the evidence from the 1968 -71 experiment shows that fewer accidents occur to children under this regime. It is quite obvious too, if you think about it. When they go to school in the dark, they are usualy traveling by car or bus, but even if walking will be "on a mission" to get there on time. In contrast, when coming home after school in the dark they will be travelling more casualy, may be larking about with friends, and more of them will be tired and less attentive. This is when accidents happen.
When you add in the recent findings with regard to energy saving the case becomes even more compelling.
I personally think we should pick a time & stick to it all year round, and there may be a good case for going to GMT+2.
If the Scotts want to stay on GMT, then let them!
Keith Obbard, Groombridge, East Sussex
The entire world sets its clocks by GMT. It would be entirely wrong to move away for this. If people have a problem they should get up earlier, adjusting themselves to the clock and not the other way round. It would be far simpler for schools and businesses to start and finish earlier than faff around with changing the clocks all the time.
HC, LONDON, UK
I totally agree with Elizabeth' Garnsey's study. This government claims to be a green party, yet it continues to return us to GMT in late October each year resulting in the rise of carbon dioxide emissions as well as 450 serious injuries on the roads and many child deaths. It's a crazy price to pay just to keep a dwindling number of Scottish farmers happy. I am a Scottish schoolteacher and I would welcome this proposed change with open arms. (and so would many others north of the border).
Anyone who prefers putting the clocks back to GMT certainly does not care much about environmental issues.
(Not to mention keeping children out of hospitals and coffins)
John Macnab, Troon, Scotland
John Macnab, Troon, South Ayrshire, Scotland
Pathetic. Why change the clocks in the summer anyway? The fact is that the further you go from the equator the shorter the days get in winter. There is no more daylight available and changing the clocks does nothing about it. Whatever you do you're going to have darkness either at the end of the day or at the beginning of the day and this will mean more energy consumption and more risk of "accidents".
Why not tell everyone to stay at home when it's dark (preferably all year round) and not run any risks at all and minimize energy consumtion that way?
Just another example of interfering busybodies with nothing better to do trying to tell ordinary people how to run their own lives.
John, Exeter, England
Basic time anywhere should be based on longitude, so logically UK should be on GMT, with an hour ahead in summer if required.
Ian Smith, Sotogrande, Spain
We should just leave the clocks at GMT and get on with our lives. Fatuous intellectualism has come up with all sorts of time zone theories and none of them work. So keep it simple. And please, don't change just to come in line with europe. They are much further east of us and need a different zone(s).
Mike Poulsen, Reading, Berkshire
I nver understood why we do this. Wasn't it the Sctos who demanded it?
Well. They are a separate nation now ....
Pete Balchin, Solicitor , Bristol, UK