An article in the Independent about the UK Conservative Party's plans for an immediate review of electoral boundaries if they become the government alerted me to a horrifying fact: not only does the UK have an unfair electoral system - it doesn't even have equal-sized electorates to lend that system a veneer of credibility. Instead, the size of electorates varies hugely across the UK, with a consequent variation in the value of a vote.
How bad is the problem? Mucking around with a spreadsheet, the list of constituencies for the next UK election, and the electoral quota for England (69,934 - based weirdly on the current electoral population and the number of seats at the last election) shows tremendous variation. In New Zealand, the acceptable variation for a seat is plus or minus 5% (and most vary by far less). In the UK, 326 seats - fully 50% of the Parliament - vary by more than that. 115 seats - 18% of the House - are out by more than 10%, and a substantial fraction of seats are out by 20% or more. Two seats - both in Scotland - are shockingly out by more than 50%.
(I should note that there are actually separate quotas for England, Scotland, Wales and Northern Ireland; I've used the English one here for convenience).
This simply makes a mockery of democracy. Democracy doesn't just require one person, one vote, but also that those votes count equally ("one vote, one value". as the Australians put it). But in the UK, the vote of someone in Na h-Eileanan an Iar is worth three times as much as that of a voter in a typical electorate, and five times as much as one on the Isle of Wight. It's not as bad as the US Senate gerrymander (in which Wyoming gets as many Senate seats as California), but at least that's justified by a federal system. This is simply the product of outdated rules [PDF], an archaic obsession with county and borough boundaries, and no hard and fast requirement for equal size. They don't even know how many seats there should be - which makes it surprising that they manage to set electorate boundaries at all.
Back in the nineteenth century the UK passed the Great Reform Act to eliminate Rotten Boroughs. It's time they did that again to eliminate their modern incarnation and ensure that everyone's vote is of equal value. Of course, the best way of doing so would be to ditch their archaic system and move to proportional representation...