One of our readers, Jim Bach, sent us some interesting seats/votes curves for the three main parties in all UK postwar elections. It is no big surprise that the line is so flat for the Liberal Democrats but it did surprise me that the slope for the Conservatives is almost twice as steep as for the Labour party. If I read the graphs correctly, Labour had a seat/vote ratio of less than 1 in 12 out of 18 elections, whereas the Conservatives were below 1 only 5 times. This suggests that there may well be more at stake for the Conservatives in preserving the current electoral system than for Labour. The same idea emerges from the Guardian’s analysis of what the results might have been under a series of alternative voting arrangements (assuming, of course, that voters do not change their behavior under different electoral rules). I’ll ask readers more knowledgeable about British politics to speculate on what may be responsible for this difference between Tory and Labour return on their popular vote shares.
