There is no two-party system in Britain, thank intellectuals. But here in London for the Mayoral Election we have transferrable votes: every voter makes a first choice and a second choice. If nobody wins with an outright 50%+ majority, the two leaders are taken, and then all the second choice votes from the losers are added to the votes of the two leaders.
I must admit it works superbly. It tells you so much more. The Liberal Democrats are failing miserably in London. Obvious, if you are aware and intelligent enough to know that we don't need unbridled liberalism any more: what we still need are people who can contain and correct all the mistakes from the Sixties Onwards liberal era. But when I think that, I am guilty of intellectual snobbery, because notice that the BNP's % votes went down a bit, and the Green Party's votes went up by even less. There is no radical change in London democracy, despite the continuing transfer of London culture into the Globalized Economic Matrix. Democracy depends on demographics, in addition to depending on political free will. Those whom have babies, create voters. The Green Party and the BNP will never get anywhere, because they haven't even got a population growth scheme such as is encouraged by religions. The Liberal Democrats are dying out, simply because they tend to be secular, and reckless, so they are neither good at reproducing, nor are they any good at keeping their existing populations alive.
Evolution and Natural Selection in London human beings, all on one page of democratic voting statistics.