BRITS head to the polls the question of a hung parliament hangs over the election for the first time in 36 years.
If one party gets more than half the seats in Parliament, at least 326 out of 650, they have enough MPs to govern.
But if no one party gets 326 seats, there will be no majority and therefore a hung parliament is created.
So who gets the keys to Number 10?
In that event, Gordon Brown would remain Prime Minister until he chooses to resign. But what if he refuses to?
Tradition, which Britain’s constitution relies on to form its Parliament, means Mr Brown, as the serving PM, would get the first chance to find enough rival parties to form a coalition that would give them 326 seats.
The wrangling could take days, weeks even, as politicians make deals behind the scenes.
Whatever happens, the Queen will come to Parliament on May 25 to announce what her Prime Minister plans to do during the next year. That then gets voted on.
So if Mr Brown hasn’t formed a coalition, his proposals would be voted down.
Then he would have to quit, and David Cameron would be given a go at forming a Tory-led coalition.
If he were to fail, Britain would face a new General Election.
The last time we had a hung parliament, in 1974, we ended up back at the ballot box within six months.
In reality, the Lib Dems’ Nick Clegg is likely to be the “kingmaker” tomorrow.
If his party joins Labour or the Tories, they are likely to be able to deliver a majority.
In return, the Lib Dems can demand the Prime Minister adopts some of their policies, specifically electoral reform.
And proportional representation, where seats in Parliament are allocated more in tune to the percentage of the total number of votes cast, is a likely outcome of a hung parliament.
That would open the door to smaller parties like the BNP, Greens and UKIP to getting seats at Westminster in future.
So today could truly change the face of British politics for ever.