Now i was just listening to the BBC news and some expert on there said that even if the Conservatives or Labour agreed to have a referendum on PR it would take about 3-4 years to get to the stage of a public vote.
Also if it went to a public vote would you have to have safeguards in place just in case there was a very low turn out to vote on it,i mean you could not justify changing the electoral system if only a few % of the public bothered to vote on it.
If it did take as suggested 3-4 years to get to the stage of a vote i don't think it would matter because whoever gets the Lib Dem support will do all they can to improve their party standing so they can have a General election and be shot of the Libs.