What are the arguments against FPTP
@rcoobc?
Ignoring that it doesn't give a "proportional" outcome (4 million votes earned UKIP 1 MP and 1.5 million votes earned the SNP 56 seats) there are a few other disadvantages.
First off, I should say it is actually a fairly decent system that has worked for hundreds of years. By and large it keeps the wackos out of office (AV would have been better for that, but we turned it down), and every MP is accountable to his or her constituency and faces losing their seat if they do a crap job.
However, the problems:
1) Your votes are pointless. No matter what way I voted in Ashford it wouldnt have made a difference. Even if I convinced all my friends, and my families friends, and my friends families, and my friends families friends to all vote Labour, it wouldnt have made a difference. The Conservative MP won by a margin of 20,000 votes out of 60,000 votes cast.
2) Each consistency has only one elected representative. If your MP is a bit crap, then you are out of luck when you've got a problem and need some help. If your MP is Tim Fallon, then maybe he will fight tooth and nail to help you out. If you happen to live somewhere that sadly elected a BNP however...
3) It creates safe seats where everyone knows what the result is going to be, so nobody really bothers to try there. The South East, by and large, always elect Conservatives, so Labour arent going to bother putting a strong candidate forward just to see them defeated. As such, a hugely disproportionate amount of money is spent to try and win the 50-100 or so seats that may change hands. In this way, the majority of the public is denied exposure to other ideas and everything stays the same.
4) It also may be very difficult to find an elected official that shares your view point.. If you want to legalise weed, then you are going to have to go a long way from the South East to find an MP that likely shares that view. If you support the union in Scotland (as over 50% of the Scots appear to), then you almost have to leave Scotland now to find an MP that shares your opinion.
5) It's a bad way to choose anything. In X Factor, do they choose the winner on peoples first preferences on the first day? No, they do round by round voting until there are only a few candidates left. (Okay they also have judges that do stuff). In Business, you also almost always use round-by-round voting to narrow the options down until a clear choice emerges.
6) You can have a split vote. If there is a very liberal constituency, but the Lib Dems, Labour and the Green party are all competing, then there is a chance they will all cancel each other out and the Tories will get in. Same with UKIP and the Torys. 60% of a consistency may not mind between the Tories and UKIP, but as the vote is split, a Lib Dem gets in.
7) Nothing is proportional.
There are probably more.
Edit : oh yeah tactical voting. You want a green but vote Labour as you know your vote for the Greens is pointless. You want labour but known you'd be better of voting Lib Dem to stop the Tories in your area