The Party System is not permanent - necessarily

Thanks to Maajestic. I think a referendum on the EU is in everyone's interests. I wonder if there is a possibility, after an inconclusive election result, which seems likely, that a short term pro EU coalition might be formed containing Labour, Lib Dem, SNP and a section of the Conservative Party. In the same vein I wonder whether the Conservative party might split over Europe. We assume that parties will stay together for ever, a bit like marriages when they start, but there is no reason why parties should not split, especially if the two party system collapses. Thinking off the wall, what about a coalition between the Conservatives and a section of Labour (like the Conservative/Liberal coalition of the early twentieth century which split the Tories? My feeling is that what is most likely post May 7 is a short lived minority government followed by some sort of re-alignment in British politics and another election.