Stolly,
Witton Park above reckons "Our system works well", I am not sure I agree with him. Personally I think both the Tories and Labour are too "broad a church". The Tories have been hampered for decades by the hard right of their party, and now labour has lurched to the hard left. This leaves the moderates in both parties in a difficult place. I personally would be comfortable with a coalition consisting of some mixture of Tory Wets/Blairites/Lib Dems/SNP, which would require both of the big parties to split.