How we could equalise constituency sizes

Nigel Williams, 2 May 2013

Three parts of the coalition agreement were a referendum on AV, House of Lords reform and evening up parliamentary constituencies. The referendum has happened and failed. The other two are mired in disagreement between the partners. For many people, AV was not ideal and only appealed as less bad than some of the alternatives. In the many years before another referendum can happen, it is worth an occasional look at other systems. One could deliver equal constituencies at the same time.

This scheme proposes:

• Draw the boundaries after counting the votes.
• Allow boundaries to be different for each party.
• Make constituencies equal by votes cast, not registered electors.
• Award seats to parties in close proportion to votes cast.
• For each party, divide the country into constituencies so that each had the same number of votes for that party, around 45 to 50 thousand. Each voter would get an MP from each successful party.

In practice, if the Conservatives polled 35 per cent and got 228 out of 650 seats, they would spread their most popular 210 candidates across the country, with higher density in Conservative strongholds. If Labour had 38 per cent and 247 seats, they too would cover the country, sparse (large geographically) in mainly Conservative areas but dense (geographically small) where Labour support was stronger. Each voter would be represented in Parliament by both MPs and others besides. A putative 60 UKIP constituencies would be larger geographically but spread fairly equally around the country.

The algorithm for dividing the constituencies needs a little care. It is best if the electors, not the parties, choose the successful candidates. Candidates are put on a polling station’s ballot paper, with a party name too if they belong to one. They may only stand in contiguous polling stations. In working out a party’s most successful candidates, they can be ranked by the number of votes by which they exceeded their party’s average proportion of votes cast. Some seats would remain relatively safe but it would still be down to the voters to choose.

For each successful candidate, draw a constituency boundary where they received an equal number of their party’s votes. Start where each received the greatest density and add party votes from adjoining polling stations, making some allowance for coastal areas to maintain contiguity.

The results: each MP speaks for the same number of voters and almost every voter has a small share in an MP from a first-choice party. Every vote counts and the constituencies are genuinely equal. Just don’t expect it to win a referendum at all soon.