We absolutely do need electoral reform for the House of Commons. The system at the moment has a number of major deficiencies including:
1)     Parties can gain an overall majority on a share of the vote that is nowhere near a majority. This almost always happens and in undemocratic. Although over the years Labour and Conservative both get their turns in power in our system and hence their voters are represented in government and governing decisions, the principles of the 20-odd percent that vote Lib-Dem or Green or UKIP get no governmental representation at all. In the case of UKIP and the Greens they get no parliamentary representation at all.
2)     People on here may not thank me for saying this but it is heavily biased in favour of Labour. If both Labour and Conservative got the same percentage of the popular vote, Labour would have many more seats than the Tories. This is fundamentally unfair and undemocratic.
3)     It focuses most political debate on a narrow sliver of the electorate. The few hundred thousand swing voters in marginal constituencies who effectively decide the outcome of elections. The means that often, but especially at election time, debate becomes focused on narrow issues of particular interest to this demographic (generally middle earning, middle class types). This leads to the sort of policies you outline in the blog post.
4)     It is harder for candidates who do not fit the typical white, middle class, middle aged, male criteria to become selected because each constituency party wants to win their seat and this is the sort of criteria that they are generally most comfortable with and with which they think they are most likely to win. If we were to use STV with multi-member constituencies then it actually starts to be in the parties interests to pick a number of candidates who taken together will be more diverse than if they can only choose one to maximise the number of votes (including second and third choices etc.) across the constituency.
There are lots of other arguments as well. I know there are arguments for First Past the Post but in my opinion, the main one (maintaining the constituency link) does not stand up to scrutiny when compared with Single Transferable Vote with multi-member constituencies. In my opinion the main reason why it is not on the political agenda is because the current system favours both major parties (Labour the most) and simple electoral pragmatism militates against any change in the status quo. This is why the government reneged on its 1997 manifesto commitment to hold a referendum on this issue once it got into power.
The Electoral Reform Society had more information on STV: http://www.electoral-reform.org.uk/article.php?id=48
Mark.

I agree that we do need some sort of electoral reform. I'm not too bothered about keeping one MP per constituency in the House of Commons, but I'd prefer to see an elected Senate replacing the House of Lords which would be voted for using PR. Give this new Senate more powers to block legislation and then we'd never see a Conservative government ramming thorugh it's legislation ever again.

Am 100% against PR. I dont want a system where the Lib Dems rather than the electorate decide who forms a Government. 

I've always been a bit skeptical as to whether it's really FPP that causes British politics to be biased towards middle-income, 'swing' voters.  After all, even under PR, victory is still ultimately going to be decided by convincing those people in the middle of society that your party offers the most for them.  If Labour's natural base is the working class, and the Conservatives' natural base is the rich, then it still comes down to how those middle-income people vote in order to break the tie.  OR even worse, down to a party that claims to represent the interests of those middle income people after all the votes have been cast.

Don't get me wrong, I'm still in favour of PR, on the basis that we have a multi-party system operating under a 2 party electoral system, which is just inherently undemocratic.  But I don't think people should get carried away about what this means in terms of electoral mathematics.  It is the middle class's position in SOCIETY that gives them their disproportionate power; not their geographical position in particular constituencies.