And it only happened because people were worried about missing their train.
Let me explain.
This morning's sunrise in Brighton was at 0656 but in Edinburgh it was 0712. Because the Earth is curved (sorry Flat Earthers), the sun comes up over the horizon at different times depending where you are on the globe. And this constantly changes.
In six months time on August 25th, sunrise in Brighton will be at 0604 while in Edinburgh it will be the same - that quarter of an hour difference has vanished.
But just a few months later on Christmas Day, sunrise will come to Brighton at 0803 and in Edinburgh at 0845 - the gap between them is now three quarters of an hour.
This wasn't a problem back in the days before people started to travel long distances - 'Local Time' was good enough. Local Time was set by observing astronomical events such as sunrise and sunset, the position of the Sun in the sky and the waxing and waning of the Moon. Sundials - the first real attempts at creating a chronometer - used the Sun to give an indication of the time of day. However, solar time is not the same as clock time and a sundial set up in Brighton will give a different reading to one in Edinburgh for much of the year. In order to get the two to match you have to make certain corrections known as the Equation of Time.
The orbit of the Earth is not perfectly circular and its rotational axis is not perpendicular to its orbit. The sundial's indicated solar time thus varies from clock time by small amounts that change throughout the year. The solar time must be corrected for the longitude of the sundial relative to the longitude of the official time zone. People far smarter than me came up with an equation to allow people to calculate the differences and these were widely published in almanacs. However, the average working man or woman paid little attention to this as it did not affect their lives. Even when mechanical clocks and watches appeared, people would often set them to Local Time rather than Greenwich Mean Time (created in 1847). What the time was in faraway London was of little interest to them.
Oh, and if you're wondering why GMT was centred on a borough of London, it's all because of the Navy. As you'll probably be aware, the Royal Naval College was built there (established in 1604). Establishing a meridian zero longitude point at the college was a way for British mariners to calculate where they were in the world by comparing their longitude to the Greenwich Mean. One chronometer on a ship was kept on GMT but this did not affect shipboard time, which was still solar 'local' time.
Meanwhile, back on the mainland, everything changed with the coming of the railways.
The inconsistencies of Local Time would have meant that setting timetables would be impossible. Therefore, the Great Western Railway adopted GMT in November 1840. Other railways followed suit, and by 1847 most (though not all) railways used London time. On September 22nd 1847, the Railway Clearing House, an industry standards body, recommended that GMT be adopted at all stations. And, by 1855, and in order for people to be able to access the railways on time, nearly all public clocks in Britain were also set to GMT (though some, like the great clock on Tom Tower at Christ Church, Oxford, were fitted with two minute hands, one for Local Time and one for GMT).
The last major holdout was the legal system, which stubbornly stuck to Local Time for many years, leading to oddities like polls opening at 08:13 and closing at 16:13. The legal system finally switched to GMT when the Statutes (Definition of Time) Act 1880 took effect.
So now you know.
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