How do we know that under PR more people would have not voted for the conservatives and that the result may have been very similar to what we have now anyway?
Oh that is right, we don't.
Also why is it necessarily fairer? I would say it could be considered more unfair that certain areas might not get the MP that the most people in that area voted for.
Well there's an argument that if the was PR then the Tories couldn't scare people with and Labour/SNP coalition and more people wouldn't have been afraid to vote UKIP, we can never truly know for sure but without FPTP a Labour/SNP would have been unable to be bigger than the Tories