There are 49 constituencies still to call, but it is clear that neither Labor nor the Conservatives will be able to reach the majority of 326 seats, even when obvious allies are added in. The Conservatives have 280 seats, Labor 240, Lib-Dems 52, others 27. Even if the Liberal-Democrats form an alliance with Labor, they fall short.

in short, Parliament is hung -- and how Britain is to be governed is just not clear. Only when the remaining seats have been called can the arithmetic (and the horsetrading) get under way. Meanwhile, the prime minister, Gordon Brown, and the Conservative leader, David Cameron, are writing the scripts. The Conservatives say Brown has lost the mandate to govern. Labor says the Conservatives have not been given the mandate to govern.

Labor ministers, meanwhile, are getting in touch with their inner electoral reformer, lining up to tell us that they have always been in favor of changing Britain's first-past-the-post voting system to allow for a fairer translation of votes into seats. They know that electoral reform is a key demand of the Liberal-Democrats, and a precondition of any coalition with Labor they might enter.

Yet is a Lib-Dem/Labor coalition government legitimate, when adding together their seats still fails to give them a majority in Parliament?

Surely the Conservatives, as the party which has polled the largest number of votes, should be able to decide how to form the government?

But that would depend on the prime minister, who constitutionally is the one entitled to form a government in the interests of stability and the good of the country. He may decide that to hang on is undignified; or he may conclude that to resign to allow a minority Conservative administration is irresponsible.

What happens now is depicted in this BBC tree. If, as seems likely, the parties fail to form a coalition that gives them a majority of seats, we are likely to see a minority government which rules as long as the other parties agree not to bring it down. But that is more likely to be a Conservative / Lib-Dem coalition than a Labour / Lib-Dem one. It would be inherently unstable -- but sufficent to reform Britain's creaking Victorian electoral system before a new election.

And what would the Lib-Dem leader, Nick Clegg, want in return for his seats? He is due to make a statement shortly.

The British people have voted  -- and voted clearly: they do not trust any party to govern on its own. They are demanding that their political leaders negotiate.

This, of course, is what happens across Europe, where there are only three majority governments; the rest form coalitions that are the result of horsetrading.

Learning to be like other European countries, however, will not be easy. The British system is essentially adversarial: the main parties face each other across the chamber, growling at each other. If they're all going to begin to do deals, they'll need to redesign the layout of Parliament.