Via Mark Thompson's blog I have been alerted to this excellent examination of FPTP (first-past-the-post) by Prof John Curtice in Parliamentary Briefing.
John is the psephologist from Strathclyde University who in 2005 said the most likely result of the next election would be a hung parliament.
Basically, it is getting increasingly difficult to achieve one party rule under first-past-the-post for 3 main reasons - 1. the declining share of vote of the two main parties. 2. the dwindling number of marginals, and 3. the ineqitable treatment of the 2 main parties.
A lot is made of the 'unfairness' to the Tories of 'only' winning 47% of the seats on 36% of the vote. Wrongly identified as the cause of this is that their constituencies have on average 4,000 more registered voters than Labour seats, but the clue there is in the word 'registered'.
When the lower registration of voters is taken into effect, Labour constituencies actually contain more potential voters and also have much more people because they have larger under 18 populations, not to mention higher workloads for MPs having to deal with the higher poverty and associated social problems.
The Tories with Lib Dem assistence are planning to make registration harder thus exarcerbating these problems and to ignore the fact that unregistered voters make Labour constituencies bigger. Lower turnout in poorer Labour seats is also the other reason why Labour can get less votes than the Tories and still not lose as many seats as Tories would on such a low national vote.
The real big problem for the Tories is the fact they cannot get more than 40% of the vote and most of that is concentrated in rural and suburban areas of England. In reality the Tories need to win some Billy Bragg types over to get large majorities, this seems unlikely to ever happen. We still remember the 80s.
The Tories want more marginals but seem unwilling to sacrifice some of their votes in their ultra-safe seats which is the only way of achieving this. It will also be interesting to see how they cull the number of MPs - Tories will want only non-Tory MPs culled - whether that is achievable I doubt.
I am going to be looking at each voting system in more detail over the next few months in the run up to the possible referendum. Starting soon with the glorious first-past-the-post system.