When do the clocks go forward and why?

At the end of the month the clocks will jump forward one hour as the UK marks the start of British Summer Time (BST).

Smartphones and electronic appliances should update themselves, but “you’ll still need to adjust your watch and the clocks around your house to avoid getting caught out”, iNews says.

The use of BST is still hotly debated in Britain. Many people “find that even the hours' difference disturbs their sleeping pattern, with many people waking a lot earlier when the clocks jump forward”, says The Weather Channel, and this disturbance “can leave people feeling tired and irritable in their day - or just confused as to what time it is”.

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So why do the clocks change and will 2019 be the last time?

When do the clocks go back?

At 1am on 31 March, the last Sunday of the month, clocks will go forward one hour, marking the start of seven months of daylight saving time.

Does that mean more or less time in bed?

Everyone gets one hour less sleep when the clocks go forward.

Why do we have BST?

British Summer Time (BST), otherwise known as daylight saving time, was originally devised to keep factories open for longer in the summer – since there was enough light to do so.

It has also been suggested that BST reduces energy consumption. In the days of coal fires and tallow lamps, this may have been true, says Forbes, but the advent of electrical light has wiped out much of this saving.

Who invented British Summer Time?

BST was proposed in 1907 by William Willett, who happens to be the great-great-grandfather of Coldplay singer Chris Martin.

Willett, a builder from southeast London, proposed the idea after growing frustrated with having to cut short his rounds of golf at dusk.

He self-published a pamphlet called Waste of Daylight, which suggested that the clocks would move back 20 minutes each day for several days, to a total of 80 minutes.

The idea was pooh-poohed, but the First World War changed the government’s views on the issue.

Germany brought in summer time in 1916 so that it could keep munitions factories open longer – and the UK immediately followed suit.

Sadly, Willett died in 1915 so never saw his plan in action.

How has it changed since then?

In 1940, the nation was put on Double British Summer Time – two hours ahead of Greenwich Mean Time in the summer and one hour ahead during winter.

This was intended both to increase productivity in the war industries and to help workers get home before the blackout began.

Harold Wilson’s Labour government experimented with a return to Double BST in 1968, even though Scotland protested that it left northern parts of the country dangerously dark until 10am. The scheme was abandoned three years later.

Why don’t we have BST all year round?

With the promise of longer days and more sunshine, over the years there have been repeated calls for British Summer Time to be made permanent.

Pros of BST all year round

Energy: Researchers at the University of Cambridge found that an extra daily hour of sunlight in winter evenings could save £485m each year in electricity bills, as people use less light and heating.

Tourism: The British Association of Leisure Parks, Piers and Attractions claimed in 2011 that lighter evenings would increase tourism earnings by between £2.5bn and £3.5bn.

Traffic accidents: The AA backs the campaign for year-round BST in order to increase road safety. The latest research estimates that around 100 lives would be saved a year by preventing accidents in the dark evenings, it says.

Economy: Even after Brexit, it would have the economic benefit of putting UK businesses in the same time zone as most of their European counterparts.

Well-being: The Manchester Evening News says children, in particular, would feel the benefit and would be up to 20% more active during the longer evenings.

Environment: Cambridge University researchers also found that year-round BST would reduce CO2 pollution by at least 447,000 tonnes each year, the equivalent to more than 50,000 cars driving all the way around the world.

Cons of BST all year round

Scotland: One of the biggest obstacles to change has come from Scotland, where MPs warned that the sun would not rise until 10am in some northern parts of the country. Alex Salmond once called the campaign an attempt to "plunge Scotland into morning darkness".

Dangers of darker mornings: The pro-BST crowd points to the dangers of dark evenings, but those against year-round BST have suggested that children walking to school in the mornings could face higher risks in the dark.

Benefits for early risers: Lighter mornings have traditionally been supported by postal workers, the construction industry and farmers. Those living in Scotland voice particular concerns about people having to travel to work in the dark.

However, the National Farmers’ Union of England and Wales says it has no strong views either way. “The last time we tested opinion among our members there was a narrow majority in favour of lighter evenings,” says director of strategy Martin Haworth. “Whether an extra hour’s daylight would be more beneficial in the morning or the evening depends very much on the work pattern on each individual farm.”

What does the public think?

A 2015 YouGov survey found that a plurality of people think it is time to stop changing the clocks. Those opposed to the twice-yearly time change outnumber those in favour by 40%-33%, but nearly a quarter of the public (23%) have no opinion either way and 4% are undecided, YouGov says.

When do the clocks go back again?

For now, clocks will continue to change twice a year. Clocks will go back one hour again at 2am on 27 October, when we will gain an hour in bed.

Which countries use daylight saving time?

Most European countries move their clocks forward an hour for summer. The exceptions are Russia, Iceland, Georgia, Armenia and Belarus.

However, the European Union is considering scrapping daylight saving time permanently.

Jean-Claude Juncker, the European Commission’s president, said that a consultation had shown that more than 80% of EU citizens were in favour of the move.

“We carried out a survey, millions responded and believe that in future, summer time should be year-round, and that’s what will happen,” he told the German broadcaster ZDF.

The EU currently uses three standard time zones. One option being touted would be to let each member state decide whether to go for permanent summer or winter time, although the commission has warned that uncoordinated time changes between member states would cause economic harm.

In the US, different time zones move their clocks forward at different times and not all states use daylight saving time.

Will the UK scrap BST?

If the UK leaves the EU as planned at the end of March, it will not be subject to any legislation regarding time changes. However, this may cause what The Guardian describes as a “clockconundrum for Belfast”, as Northern Ireland and the Republic of Ireland will be in different time zones during the summer months if the UK continues using BST.

The UK is set to leave the EU in March 2019 and thus will not be subject to any legislation regarding time changes, but this may cause what The Guardian describes as a “clockconundrum for Belfast”, as Northern Ireland and the Republic of Ireland will be in different time zones during the summer months if the UK continues using BST.

If Northern Ireland and Ireland were to operate on different times then this would “likely cause significant confusion at the Irish border”, the newspaper adds, “the arrangements for which are already one of the biggest stumbling blocks in Brexit negotiations”.

However, the UK may find itself being forced to abolish BST regardless, as the proposed scrapping of daylight savings time by the EU may occur during what’s known as the transition period, in which the UK will remain beholden to certain EU regulations for a year after its official exit on 29 March 2019.