The distribution of non-voting by voting composition in the 1987 general election.

650 parliamentary constituencies projected onto the electoral triangle (with Northern Ireland shown separately), shaded by the level of turnout — software by author on an Archimedes computer.

It is clear that the highest turnout is to be found in the Conservative party’s most marginal seats, although a few bright spots can be seen in some Labour strongholds. Northern Ireland is almost totally bereft of political will; the next largest concentration is to be found in areas of Labour control such as London.