A continuous grey scale, equalised for each election (with median shown) was used to colour the 705 consistent constituency over the ten elections on the changing equal electorate cartograms (Appendices B and C) — software written by author on an Archimedes computer.
The pattern of abstentions has altered a little over the decades. The North east has now a lower turnout, and that in Northern Ireland rose then fell. The area of the West Midlands that contains many people who do not participate has also swelled in size. Overall the average turnout has moved around quite a lot, the highest rates of abstention being in 1970, October 1974 and 1983.