The Tories at
Labour at 258
The LibDems at 57
...and the rest of the
Even with the Conservatives picking up a net of +97 seats, it's not enough.
Need 326 to carry confidence.
(*Errata: 323. Sinn Fein won't take their 5 seats, so a majority of quorum is less than 50%+1 of the entire parliament.)
There simply aren't enough minnows that would treat with the Tories to make up the shortfall.
Two possible reasonable courses for the Tories from here, IMO:
. Go with the Unionist allies, and stay in opposition. Let Labour sell out to the Liberal Democrats, and then beat them both with that stick until the government falls. Win more seats in the snap election that follows.
plus point: good for the Tories; good for the future of conservatism.
minus: probably very bad for the country. Labour under Gordon Brown has for all intents brought ruin to the doorstep. Leaving them in the driver's seat might allow more malfeasance, and certainly would allow a stubborn-and-selfish strategy by Labour to hold off calling the next election no matter how much more bad they do. There's just no telling how much national sovereignty a combination of Lord Mandelson and Nick Clegg will figure out how to give away in that circumstance.
.. Get out the splitting wedge and go after the bloc of Liberal Democrat MPs from Cornwall. Try to carve apart LD with the promise of coalition in government.
plus point: unlike doing a deal with the LibDems as a whole, an agreement with the generally more rational folks who run as LD in the far southwest would likely not require a commitment to supporting Proportional Representation as part of election reform, nor would it bind the Tories to the boat-anchor of Eurocentricism that is so dear to N. Clegg and the urban LibDems.
minus: Very, very hard to do. As divided as the heart of the LibDems is, there is rather little chance after a campaign where their leadership did a very fine job of keeping the party together in a run at both big parties that said leaders are now weak (or foolish) enough to let a dozen of their old-line go wayward on them.
If it were mine to play, I'd take a try at it, though.
Unlike Sir John (John Major; former PM and rather the cause of the Tories' years in the wilderness), I don't think giving the LibDems cabinet seats "is a price worth paying". A coalition with LD as a whole will neither be stable nor able to move decisively.
Sadly, we may well find out.