Debate over a possible coalition government has reached fever pitch with opinion poll after opinion poll hinting at a hung parliament.
If no party receives a majority, they will be forced to enter into a coalition or seek support for their policy programme from the opposition benches.
Speculation about which of the two main parties could attract Nick Clegg into a coalition has dominated the last week of the general election campaign, since his TV debate performance sent Lib Dem support through the roof.
Electoral reform is a precondition of Lib Dem support in the event of a hung parliament, but David Cameron remains opposed to the idea, despite not ruling out a referendum.
On the other hand, Mr Clegg's recent attacks on Gordon Brown and Labour suggest he does not wish to enter into a Lib Dem/Labour coalition either.