Time in UK: When Do the Clocks Change in London?

Ever had that moment where you wake up thinking you’re late, only to find out you’re an hour early? This confusion might arise due to the British Summer Time. It’s the period when the United Kingdom advances its clocks by one hour to maximise daylight during the longer days of summer.

This practice, known to many as Daylight Saving Time, has been part of the UK’s timekeeping tradition for over a century. So, sit tight as we dive into the captivating chronology of time changes, specifically focusing on the clock adjustments in London, the heart of the United Kingdom.

Historical Backdrop of British Summer Time

The concept of British Summer Time came into being in the early 20th century, thanks to an English builder named William Willett.

He proposed advancing clocks in the summer to capitalise on daylight, thereby saving energy. His proposition was finally accepted in 1916, a year after his death, during World War I to save coal for the war effort.

The history of time-keeping in the UK is tightly intertwined with Greenwich Mean Time (GMT). It was established in the late 19th century and remains the standard time against which all other time zones in the world are set.

The Royal Observatory in Greenwich, London, lies at the heart of this system. However, during the summer months, the UK switches to British Summer Time, which is GMT+1, returning to GMT when autumn arrives.

When Do the Clocks Change in London?

The change to British Summer Time typically happens in the last week of March. The clocks go forward by an hour at 1 am GMT on the last Sunday of March, implying that we ‘lose’ an hour of sleep.

On the other hand, the clocks ‘fall back’ to GMT on the last Sunday in October at 2 am, gifting us an extra hour of sleep.

When Do The Clocks Change In London
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So, if you’re in London or any part of the UK, make sure to adjust your clocks accordingly, or you might end up being an hour early or late to your appointments.

Don’t worry, most digital devices adjust themselves automatically, so you’ll likely be on time for your next Zoom call!

Why Do the Clocks Change?

You might be wondering why we go through this yearly rigmarole of changing clocks. The main reason for the change is to make better use of daylight.

By shifting the clock forward, we essentially move an hour of daylight from the morning, when it’s less needed, to the evening, when activities are typically more prevalent.

British Summer Time Why Do The Clocks Change
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Furthermore, this time change was initially implemented to save energy. The logic is straightforward: the more daylight we have in the evening, the less electricity we use. Despite the advent of modern technology and energy-efficient practices, this principle still somewhat holds.

However, the time change is not without controversy. While some people appreciate the longer daylight hours in the summer evenings, others dislike the disruption caused to their sleep patterns and daily routines.

Understanding the Concept of ‘Spring Forward, Fall Back’

If you’re still finding it hard to remember when the clocks change and in which direction, then here’s a handy phrase for you: Spring forward, fall back. This saying is a simple way to remember how British Summer Time affects our clocks.

  • Spring forward reminds us that in spring (last Sunday in March), the clocks go forward by one hour as we enter British Summer Time. This might mean one less hour in bed, but it also means that the evenings get lighter, and we can enjoy an extra hour of sunlight at the end of the day.
  • Fall back is a cue that in autumn (last Sunday in October), the clocks go back by an hour, reverting to Greenwich Mean Time. This means an extra hour of sleep – a bonus many of us look forward to! But it also means that the evenings get darker sooner.

So, next time you’re unsure about when and how to adjust your clocks, remember the phrase “spring forward, fall back”. It’s a simple, foolproof way to keep track of the clock changes for British Summer Time.

Understanding Greenwich Mean Time (GMT)

Now, let’s delve deeper into Greenwich Mean Time (GMT). GMT is a time system originally referring to mean solar time at the Royal Observatory located in Greenwich, London. In many ways, it’s the world’s timekeeper, as it serves as the reference point for setting clocks and time zones around the globe.

British Summer Time Big Ben Building
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GMT doesn’t change with the seasons, but it’s worth noting that the UK doesn’t use GMT all year round. Instead, during the summer months, the UK switches to British Summer Time, which is GMT+1. This shift helps to extend evening daylight in the summertime, which can lead to various benefits, including energy conservation and increased opportunities for outdoor activities.

However, the term GMT can sometimes cause confusion, as it is often used loosely to refer to the UK’s time zone, even when the clocks have been advanced to British Summer Time. To avoid this confusion, many prefer to use the term ‘UK time’ to refer to whatever the current clock time is in the UK, be it GMT or BST.

Time Change on Iconic Clocks

Have you ever wondered if time changes apply to monumental clocks? Let’s take the most iconic clock of all, the Big Ben, for instance.

Is the Time Changed on Big Ben?

Yes, indeed! The time on Big Ben, London’s renowned clock tower, is also changed according to the switch from GMT to British Summer Time, and vice versa. Despite its monumental status, Big Ben is not exempt from this nationwide adjustment.

The task of changing the time on this iconic clock is undertaken by a team of horologists, which involves a delicate process of adjustment to ensure accuracy. They also take this opportunity to carry out any necessary maintenance and checks on the clock mechanism.

Frequently Asked Questions (FAQs)

Do All Countries Observe Daylight Saving Time?

No, not all countries observe Daylight Saving Time. While many countries in Europe and North America implement this practice, most countries near the equator do not.

The reason behind this is simple: daylight hours in these countries change very little throughout the year, so there’s little to no advantage to moving clocks forward or back.

What is the Impact of Time Change on Health?

Time change can affect individuals differently. Some people might feel out of sorts, experience difficulty sleeping, or find it challenging to concentrate for a few days after the time change. These effects are typically short-term and wear off once individuals adjust to the new schedule.

How Does Time Change Affect Businesses and Industries?

The effect of time change on businesses and industries varies. On the one hand, sectors such as retail, sports, and outdoor recreation may benefit from the additional daylight hours in the evening.

On the other hand, the broadcasting industry and other sectors that rely on strict scheduling can face challenges due to the time change. However, most businesses today have adapted to these changes, minimising any disruption.


In conclusion, the practice of adjusting our clocks in the UK, known as British Summer Time (BST), is a century-old tradition that aims to make the best use of daylight.

We “spring forward” by moving our clocks an hour ahead on the last Sunday of March, and “fall back” to Greenwich Mean Time (GMT) on the last Sunday of October.

This adjustment, applicable to all regions including London, is an essential aspect of UK time that impacts our daily routines and various sectors of society.

While it might cause some temporary disruptions, the longer daylight hours it brings in the evenings can enhance our lives in numerous ways.