Nope. And probably never would be. Even countries which seem to have a single party majority under PR (the UMP in France) are actually coalition parties if that makes sense? Germany has a lot of parties in a power sharing coalition and it works fine so it's not necesarily a bad thing. It just isn't the way our system works and the House of Commons would need a redesign to make it more coalition friendly. It's very adversarial at the moment.
It's interesting to speculate.
1 school of thought says more people would have voted Lib Dem but didn't because keeping Lab or Con out in a Lab/Con marginal is more important.
Another says fewer votes for the LDs who are 'the alternative' in Lab or Con safe seats.
1 says more power to the minority parties with more representation as a Green vote is no longer a wasted vote.
Another says you would need a % bar to prevent too many little parties getting in, effectively locking minorities with widespread support out but aowing those with highly localised support like the BNP in.
Then there's the questionof what happens to the Nationalists under a national PR vote. They tend not to get a big enough share nationally to be significant but they're obviously wanted at constituency level.
Too many variables in how it would be carried out to give a firm answer but coalition and negotiation/consensus almost inevitable.