The new boundaries wouldn’t have solved main driver of pro-LAB bias in system – lower turnout in LAB seats. See chart twitter.com/MSmithsonPB/st…

— Mike Smithson (@MSmithsonPB) January 15, 2013

I’ve published this chart before which is based on data prepared by Professor John Curtice of Strathclyde University and others after the 2010 general election and seeks to show one of the big drivers of “electoral bias”.

The first set of data shows the average electorate in LAB and CON constituencies last time. There is a difference – 72,435 in CON seats to 68,612 in LAB ones but the gap is nothing like as large as is widely perceived.

Just look at the second group – which shows the average aggregate votes cast in CON seats (49,436) compared with 41,842 in LAB ones.

The reason is turnout. The average level in CON seats was 68.4% while in LAB seats it was 61.1%. It is this gap which is behind much of the distortion.

In Labour’s heartlands, where the outcome is not in doubt, far fewer people bother to vote. This is not something you can change with legislation.

Unless there’s a drastic change in voting patterns, which I very much doubt, there will still be a much higher vote threshold for the Tories to win an overall majority than Labour however much you bring average seat sizes into line.

Mike Smithson

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