In 2024 clocks go forward on 31 March and go back on 27 October. British Summer Time, also known as BST, starts on the last Sunday of March and ends on the last Sunday of October, which means that it lasts for most of the year. 

A black clock with colourful numbers lying in the middle of a bright yellow background.

Many countries use similar systems, for example in America it is referred to as Daylight Saving Time and is slightly longer since it begins on the second Sunday of March and ends on the first Sunday of November. 

The phrase Spring forward, Fall back probably rings a bell for many across the world. Taught to us at school, it is a very helpful mnemonic to help us remember which way to adjust the clocks.

The History of British Summer Time

Early Attempts

The first attempt to introduce a change to how we kept time in summer was in 1908 when the Daylight Saving Bill was debated in the house of commons. Winston Churchill said of it at the time "I have read the Report of this Committee with much interest and with a lively recognition of the advantages which the Bill in question appears at first sight to offer to all classes, and especially to the working classes".

There was a lot of interest in adopting the bill, however, some people showed concern over how it would affect businesses, especially the Stock Exchange. The bill ultimately failed, but a political interest in adopting Daylight Saving Time remained. 

Part of the War Effort

British Summer Time was first piloted in a 1916 piece of Legislation called The Summer Time Bill. Britain was not the first country in Europe to introduce a seasonal clock change, Germany had done so a few weeks earlier. Many countries did the same, following Germany and Britain's example.

At one end we treat the hours of daylight as if the sun had not risen; at the other we spend millions upon artificial light which, because it is artificial, is inferior to and is obviously much more extravagant than sunlight, which costs us nothing (Marquess of Lansdowne)

Arguments made supporting the act included suggestions that it would boost the economy (by reducing the reliance on electricity and coal), and that it would give society more sunlight which would boost morale. 

During the reading of the bill in Parliament, it was made clear that the measure was intended to be temporary. To be renewed annually only while the First World War carried on, to help the army divert resources such as coal to the war effort. 

Beyond The War

The temporary measures proved to be not so temporary! In 1925 the Summer Time Bill was debated again by Parliament, but this time the debate was over whether the changes should be permanent or not. The bill was approved with a large majority and with a few exceptions has mostly remained the same ever since. 

The best I can do is to introduce and make permanent legislation which we already have, so that we can enjoy the summer weather to the full, and so that we can obtain that improved health and increased happiness which all the authorities assure us is the practical result of recreation and exercise in the fresh air and in the sunshine.

Summer Time Oddities 

Whilst the annual clock changes have largely remained unchanged since 1925 there have been some exceptions:

  • In 1941 the UK adopted a different system called Double Summer Time. That October the clocks did not go back but stayed an hour ahead. The following March the clocks went forward again, so in summer the clocks were GMT +2 and in Winter GMT +1. The reason was to reduce fuel costs and help people during the war to get back home and adhere to the blackout regulations. The UK returned to British Summer Time hours in 1947.
  • The UK tried another system which was called British Standard Time between 1968 and 1971. During this time the clocks did not change during the year and instead remained on GMT +1. The change was made to see whether there would be a change in the number of fatal accidents on the road. The results were inconclusive and for that reason, the clocks again returned to British Summer Time.
  • There was a report made in 2010/11 into whether a change to the clock would be beneficial. The benefits were reported to be environmental; Climate “at least 500,000 tonnes of carbon dioxide saved each year"; and safety, with approximately 100 lives a day from road accidents, and in doing so saving £138 million per year. Despite this, the bill was dropped and never made it to the House of Lords. 

Changing Big Ben

Big Ben in London with a blue sky background.

Maybe one of the most famous clock towers in the world, Elizabeth Tower, home to the bell Big Ben, is also changed twice a year when the clocks go back and forward. With four faces, each hour hand weighing three hundred kilograms, and each minute hand weighing one hundred kilograms, this is no easy feat!:

  • On the weekend we change the time, it takes five hours to change the clocks on Elizabeth Tower ('Big Ben'), during which big ben itself does not chime, meaning it is silent between 9 pm and 2 am.
  • The lights on the faces are switched off while the hands are turned and put into their new position.
  • When the lights are turned back on, and the clock chimes, the hands have been moved with extreme precision by a team of five mechanics into their new positions. 
  • As well as correcting the time on 'Big Ben' the team of mechanics is also responsible for changing the time on over 2000 clocks in The Houses of Parliament. 

Double check!

Whilst technology has many advantages one of the concerns people have when they wake up on Sunday morning after the clocks have changed is 'how do I know they actually changed?'. In some ways changing the clocks manually gave a bit of reassurance that the change was actually happening. The best thing to do that morning? Double-check the time online or text a friend to make sure your phone/watch or computer is not going to mislead you all day.