Data was heavily pre-processed before being visualised in Tableau.

One can explore the visualisation online via Tableau Public.

The source was survey data collected between May and June 2013. The data illustrated represents the sample of postcoded residences with full measurement of their connection. Notably, broadband coverage provides some inference in terms of population density although office and home locations are not known. Source: http://data.gov.uk/dataset/broadband-coverage