The Lib Dems main policy and the only policy they had the power to implement was “If there’s a hung parliament, we’ll insist on proportional representation as the price of our support”. According to this policy, proportional representation would have been imposed for Westminster elections, without a referendum, effective immediately. As far I could see, we’d then have had another general election later on in 2010 under PR. The result of this would have been that no single party had a majority and another coalition government would have been formed, but of a different composition to the one formed in May 2010. There would definitely have been a lot more Lib Dem MPs, more Green MPs, and who knows what other parties?
Thanks to the Lib Dems betraying their main policy, their supporters (including me) have been deserting them until it’s now got to the point where they’d probably need PR just to get about the number of MPs they’ve got now!
Unless something drastic happens soon, we’ll find that the Lib Dems have consigned themselves to history. The Conservatives may be biding their time until they’re ahead in the opinion polls. Then, so long as no binding agreement is in place, they can call a motion of no confidence and withdraw from the coalition. The result of this would be a return to a two party system, very little difference between each party’s policies, and no hope of getting rid of first past the post.