Until late in the 19th century, time was somewhat arbitrary. Each town set whatever clocks it had to its own best estimate of local time. With the coming of the railways, however, more uniformity became desirable, and the Statutes (Definition of Time) Act passed by the Westminster Parliament in 1880 decreed that the standard throughout Britain should be "the Mean Solar Time observed on the meridian of the transit circle telescope of the Old Royal Observatory at Greenwich" - a concept we have come to know as GMT.
The same statute, in fact, gave us a measure of independence here in Ireland. It gave us a time zone of our own: Dublin Mean Time, which applied throughout the island until 1916, was 25 minutes behind GMT. Since that year, however, there have been only short periods when Britain and Ireland have been chronologically out of step with one another.
Around 1907 one William Willett, a wealthy builder from Chelsea, had a bright idea. It occurred to him that everyone in Britain got out of bed too late during the summer months, thereby shortening the time available to them for outdoor recreation in the evening.
Since people's habits are difficult to change, his solution was to change the time instead; he suggested four successive 20-minute advances of the clock as spring turned into summer. Willett organised a campaign with this objective, and succeeded in having a Bill introduced to Parliament to this effect.
But there was little public enthusiasm for the change. In the middle of World War I, however, on March 31st, 1916, the Germans advanced their clocks an hour in the interests of economy and productivity. When Austria followed suit, and then the Netherlands, Willett's ideas began to make more sense, and an "us, too" Bill was quickly enacted into British law.
The measure encountered its share of opposition. Farmers objected because for much of the time they would have to get up in the dark to milk their cows. It also meant, they said, that harvest workers would be idle for an hour as they waited for the dew to disappear.
But the idea caught on. Although "Spring forward - Fall back" lapsed after the war, it was reintroduced in 1922 and has been with us almost ever since. When war broke out again, Double Summer Time - two hours in advance of GMT - was introduced for a few years in the early 1940s, and was used again in 1947.
But an attempt to use summer time right throughout the year, introduced in 1968, lasted only until 1971.