There has long been debate over the exact location of the geographical centre of the United Kingdom, and its constituent countries, due to the complexity and method of the calculation, such as whether to include offshore islands, and the fact that erosion will cause the position to change over time. There are two main methods of calculating this "centre": either as the centroid of the two-dimensional shape made by the country, or as the point farthest from the boundary of the country. These two methods give quite different answers.

Haltwhistle is a market town and civil parish in Northumberland, England, 22.9 miles east of Carlisle and 36.8 miles west of Newcastle upon Tyne. It had a population of 3,811 at the 2011 Census.