Somebody will be invited to form a minority government. If that government doesn't get past vital votes in the Commons there will be another election. If there's a ton of squabbling as to who will support who, and the horse-trading doesn't deliver, Cameron will probably carry on for a bit then there'll be another election in October-ish. He'll be able to blame everyone else for causing another election, which nobody really wants, and will waltz back in. But by then it could well be Boris, as call-me-Dave will have lost credibility, having been unable to win two elections in spite of his opponents only being Brown and Miliband. This hellish scenario could be avoided if Labour can miraculously hold on to a lot more Scottish seats than expected. So, Scots, who d'ye want? Cameron again did I hear you say? Great! All you have to do is vote SNP!

The fixed-term deal won't prevent any of that.