Talk of a possible hung parliament is back on the Westminster agenda as an increasing number of commentators and politicians predict that no party will have an overall majority of MPs after the general election in 2010.
The shadow Business Secretary, and former Chancellor, Ken Clarke provoked consternation in Tory ranks in November 2009 when he said that a hung parliament would be a "bigger danger than a Labour victory" - suggesting it would take a generation for the British public to become accustomed to dealing with coalitions in power.
And speculation about a possible tight finish to the next election has once again focused attention on the Prime Minister's plans for electoral reform.
Gordon Brown has pledged that, if Labour is re-elected, he would hold a referendum on replacing the first-past-the-post voting system for electing MPs with the Alternative Vote (AV) system, which would rank candidates in order of preference, with votes continuing to be re-allocated until one of the candidates achieved more than 50% of the vote.
There are suggestions he now wants to push legislation on holding a referendum through parliament before the election - a move seen by some as an attempt to give himself an important bargaining chip with the Liberal Democrats if Nick Clegg were to end up holding the balance of power in a hung parliament.
It's a scenario many Lib Dems dream about - though they wouldn't say so in public.
So what if the next election does produce a hung parliament?
It's a rarity in British politics but we have been here before, in the 1970s, the era of the Lib-Lab Pact and all that!
In the February 1974 election, Ted Heath tried to face down the miners after their pay strike led to the Three Day Week. To his battle cry of 'Who governs Britain?', the voters replied 'Not you, mate.'
Heath's Tories won more votes than Labour but four fewer seats - and no party had an overall majority of MPs, creating a hung parliament.
But Heath refused to accept defeat and spent the weekend trying, and failing, to stitch up a deal with Jeremy Thorpe's Liberal Party. He finally resigned, his grand piano was famously filmed being removed from Downing Street - and Labour's Harold Wilson moved back in.
As the new Prime Minister, Wilson had two choices:
Either to seek a coalition, or some other sort of deal, with another party or parties whose additional votes would make up a Commons majority and stave off parliamentary defeat ...
Or to take the risk of going it alone - appointing ministers, pushing the levers of government, running the country and putting together a Queen's Speech of proposed new laws.
If that Queen's Speech got through the Commons and wasn't defeated by a combination of opposition parties, then the minority government could continue in office until it was defeated or there was another election.
Wilson opted to form a minority government and survived until he called a second election that October, which gave Labour a tiny overall majority of three MPs.
But this majority was soon whittled away, leaving Wilson's successor, James Callaghan, leading another minority government. Technically, if all the opposition parties had voted together, they could have then defeated the Callaghan government and forced another election within a few months.
But Sunny Jim limped on for several years by forming, first, the Lib-Lab Pact and then doing backstairs deals with the Nationalists and other MPs. He was finally defeated on a Vote of Confidence put down by Margaret Thatcher ... by just one vote.
Thatcher's successor, John Major, also lost his Tory majority - in 1996 - but limped on for another year before the Labour landslide that brought Tony Blair to power.
