That's a lot to do with their policies though. The Greens are not really different to Labour, Lib Dems ... I don't think even they know what they stand for thes

That's a lot to do with their policies though. The Greens are not really different to Labour, Lib Dems ... I don't think even they know what they stand for these days. A better recent example was UKIP. A single issue party that managed to accrue enough of the vote that they got their issue implemented without ever having to win an election. In FTFP you can implement massive change in politics, without needing to actually replace one of the big parties.