one but several MPs - reflecting the relative share of party support in the area. By thus taking account of the spread of voter preferences, the problem of the wasted vote is minimised. It also makes it easier for smaller parties and independent candidates to get a foothold.

Does anyone actually use PR?

Most of the world's democracies and almost every single one of Europe's. Though PR may sound as boring as brown rice, countries going democratic for the first time - South Africa in the 1990s, or post-Saddam Iraq - almost always choose it. Proponents claim this has to do with its evident fairness. Cynics say it has more to do with the fact that PR tends to solidify the power of party bosses over their party's candidates.

Does PR solidify party control?

It often does in practice because party leaders like to operate on a 'closed party list' basis - meaning it's the leaders who determine the ranking of their party's list of candidates in each constituency, the voters just put their crosses by their preferred parties. So if a party - say Labour - then wins two out of the three seats up for grabs in a given constituency, the two chosen will be the two at the top of Labour's list. That's how it's done in elections for the European Parliament, for example. In PR systems that use open lists, on the other hand, voters vote for individuals standing for the different parties and so have a say in which candidates get to parliament. To that extent the electorate has a closer connection to its MP than it does under Britain's first-past-the-post system, where, for all the talk of the MP/constituent relationship, voters think in terms of party rather than candidate.

How do PR-elected governments differ from f-p-t-p ones?

Since PR throws up more diverse parliaments, governments tend to be made up of coalitions - with all the problems, and some would say benefits, that entails: furious horse-trading between possible allies; compromises that bear scant relation to the manifesto commitments made by any single party; and failure to agree (in 1990s Germany a huge majority of the electorate and MPs agreed tax reform was necessary, but when it came to the details, no coalition could reach consensus). PR systems can also give rise to 'king-making' parties that wield disproportionate influence due to their ability to make and unmake coalitions (think of extremist religious parties in Israel, say).

But it still gives a 'fairer' result?

Perhaps, but the main charge aimed at PR is that it encourages voters to believe a functioning government can be constructed out of their kaleidoscope of preferences, when in fact, politics is about choosing one path over another. "We declare war or we don't: we cannot declare an 85 per cent war on the ground that 15 per cent of the electorate are pacifists," as Matthew Parris put it in the Times. Indeed, as Kenneth Arrow showed with his 'Impossibility Theorem', for which he won the Noble Prize for Economics in 1972, whenever more than two people are faced with more than three options, there can be no such thing as a rational decision reflecting the will of the people. In their various guises, electoral systems are all just ways of defying this fact.