It depends on how the remaining few seats pan out, but it is looking increasingly likely that neither a Labour/Liberal Democrat coalition or a Tory minority government with ad hoc and Ulster Unionist support will win enough seats to be able to govern effectively.
So the likely outcome is that one of those two scenarios will struggle along for the next few months until their position becomes untenable and we end up going to the polls again. This throws up another interesting scenario.
Because, if Cameron gets to form a Tory minority government it is likely that Brown will stand down and be replaced by David Miliband. Much as I abhor Miliband, the media like him and he isn't tainted in the same way that Brown is - and as such he will probably be able to bolster Labour support much more effectively than Brown.
Although that may not be enough to give Labour an overall majority, it will probably be enough to give a Labour/Liberal Democrat coalition enough of a majority to govern with some degree of authority - and leave Cameron out in the cold.
All of which is quite ironic - as the best bet for Cameron is for Brown to remain PM. It's also something of a conundrum for Cameron. If he is seen to have failed to unseat the most unpopular PM in modern times after the Tories had been out of power for four elections and with the state of the nation in a more perilous state than it was at the start of the depression then he will be seen to have failed.
But if he does become PM in a minority Tory government then he is likely to be facing a fresh challenge in months which he may well lose.
Either way, Cameron is looking like a loser.