Most of the population of Britain is effectively disenfranchised. As a reminder, about 350 people yesterday chose the new MP for Bromley and Chislehurst. White, middle-class male, non-Tory-A-lister, barrister Bob Neill is he. Like the majority of the UK's population, the good people of B&C live in a non-marginal seat. In these the MP is chosen by the party members of the constituency from a list over which their Party organisation has, depending on the party and constituency, quite a lot or hardly any influence.
There’s almost no chance that Mr Neill won’t win the by-election however hard the local Labour and LibDem activists might try. PR wouldn't end this peculiar situation. There are at least 57 varieties of PR none of them completely satisfactory. It could even be argued (although not very convincingly) that FPTP is one of them. Whatever system is in place, getting past the local party’s selection system will be the highest hurdle anyone has to face.
If you want to have any influence over who your next MP will be, join whichever party always wins in your constituency. Or if, like me, you live in a marginal, join one that has a chance. Sound advice except that to follow it would mean me joining the Tories or LibDems. Arrrg, advice is so much easier to give than to take......