Anotheoldgit, regarding your analysis of FPTP - I think this needs a bit of extra attention, as the devil is in the details here.
You're right to point out the flaws inherent in the FPTP system, but it's silly to wave away a mandate won off the system as totally illegitimate (as I'll show in a minute). Firstly, I'll cover the problem in the system so people know what it is:
An MP in FPTP needs a plurality at the constituency level. This means even if s/he gets the largest number of votes, said candidate can be elected without a majority. Take a look at these figures from the constituency of Argyle & Bute in 2001:
Con: 20.8%
Lab. : 24.5%
L-D: 29.9%
The Liberal-Democrat candidate gets in, but when 45.3% of the constituents voted against him.
Now, that's a significant (and infuriating) problem with the system, but to wave off a mandate won under such a system as completely illegitimate is silly. For example, look at what the 2005 General Election results would look like under a totally proportional system (if everyone voted the same):
Lab: gained 35.2% of the vote, so would get 227 seats
Con: gained 32.3% of the vote, would get 209 seats
L-D: 22% of the vote, would get 142 seats
So, Labour would still be in government, provided it could forge a coalition with the Lib-Dems. So the mandate provided by FPTP is inflated (and I'd agree in that it's seriously flawed), but it's not illegitimate.