Flows drawn between the 17 level II European regions on equal population cartograms, width of arrows and size of circles in proportion to the number of people moving — software by author on an Archimedes computer.
These four diagrams show the effect on the flow map of gradually lowering the threshold for including a particular migration stream. When one percent of the two areas’ populations must be involved, only the link between London and the rest of the South East is shown. With the threshold lowered to half of one percent, links between the other major conurbations and their hinterlands appear, all net flows being outwards. At a fifth of one percent a chain has formed, connecting Tyneside (by association through other regions) with Wales, but excluding flows to the North West and Scotland. At a 0.1% level 95% of the people who moved between these regions are shown, and a pattern of long distance migration is established, dominated by movement in the south east of England.