|The last time Britain saw a hung parliament was in 1974 [GALLO/GETTY]
The phrase "hung parliament" has seldom been used in British politics. It doesn't happen very often.
It's common enough in countries with proportional representation voting systems, like Germany or Italy.
But the last time Britain saw a hung parliament was in 1974 – 36 years ago. Before that, the only hung parliament was after the election of 1929.
This year though, the prospect of a hung parliament is looming large. Some believe voters will decide that neither leading party – or party leader – deserves all the power.
A hung parliament arises when no single political party has enough members in the House of Commons to push through legislation – so power hangs in the balance.
The reason it doesn't happen often in Britain is simple: the first-past-the-post voting system usually leads one party to emerge as an outright winner over the others.
Britain has 650 voting regions – or constituencies – and at election time each "returns" a member of parliament with a seat in the House of Commons.
In theory at least one party could win each and every seat. The winning party does not even need half the popular vote to do it.
Of course that hasn't happened, but it is normal for one single party to win more seats than the rest – giving it a majority - and with it the ability to form a government.
For the last 13 years that party has been Labour, first under Tony Blair, and now under Gordon Brown.
So, if there is a hung parliament what would happen?
Well, Gordon Brown would remain prime minister.
He has already said he would fight on if there's a hung parliament. But he would have to form alliances with other parties, by offering policy concessions and, possibly, senior cabinet jobs.
He would rely on the smaller parties for their votes to get legislation passed, or at the very least, rely on them to back him if his government came under direct threat of a vote of no confidence.
If he cannot do the necessary deals, the opposition Conservatives under David Cameron could try and muster the support for a vote to bring the government down. A fresh election would then be held. In 1974 the government collapsed within months.
One person with much to gain in a hung parliament is Nick Clegg, the leader of the third party, the Liberal Democrats.
He could be left with a big decision – to back either Labour or the Conservatives. He would effectively become the King Maker.
Britain's parliamentary system is by its very nature adversarial with MPs voting along party lines.
The "big two" rarely offer one another real support except in international affairs, and then often grudgingly.
For years, voters have been asking whether that is the best way of running a country.
Reformists favour more consensus, they want a government which makes decisions without slavishly following party interests. Under a hung parliament that could be an outside possibility.
One thing is for sure – without multi-party deals under a hung parliament the government will be dissolved and a fresh election called.