12
Jan
2012
0

Where is the centre of Great Britain?

We’re often asked this and it’s been a bone of contention for many years. As the mapping agency for Great Britain, it’s our job to survey the features of the landscape – and not to determine the centre of Great Britain, but we still get asked regularly. Views vary widely as people disagree on the definition of Great Britain, how you determine the centre and how accurate the calculations are.

A surveying expert will tell you that there can’t be an absolute centre for a three dimensional land mass sitting on the surface of a sphere and surrounded by the ebb and flow of sea water. The tides alone mean that the shape and size of Great Britain changes on a constant basis. Nevermind the consideration of whether to include Great Britain and her islands or just the mainland itself…the simple fact is that different projections, scales and methods of calculation will produce different results.

So where is the centre? We made a computer calculation based on our 1:625 000 scale mapping to find the centre of Great Britain (including 401 associated islands). The calculation was achieved by linking our 1: 625 000 database with a computer programme based on the standard mathematical principle for determining the centre of a two dimensional irregular object. In basic terms, the principle calculates the point at which the object would balance horizontally on the head of a theoretical pin – its centre of gravity. This is sometimes known as the ‘gravitational method’ and has been used as a scientific application by everyone from Captain Cook to NASA.

The computer calculation resulted in a location 7 km north west of Dunsop Bridge, Lancashire, by Whitendale Hanging Stones on Brennard Farm in the Forest of Bowland. If you consider the mainland only, the location is 4 km north west of Calderstones Hospital near Clitheroe, Lancashire. The mainland result confirmed the findings of analogue experiments carried out by a Brigadier Winterbotham, reported in the Geographical Journal in 1941.

However as with all such calculations, the level of accuracy is limited by the scale of data used. At the 1: 625 000 scale, the precision of the reference will be to a few hundred metres.

Some people argue that the furthest point from the sea should be considered the centre of Britain. We have found this point is just east of Church Flatts Farm, about a mile south-east of Coton-in-the-Elms, Derbyshire.

Other people say that Haltwhistle in Northumberland also has a claim to be the centre of Britain based around finding the mid-point along the mainland’s longest line of longitude.

Any claim is open to interpretation and the location of Britain’s true centre may never be entirely clear – but the calculations we have made are as close as we feel we can get to a question that is likely to generate debate for many years to come.

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