The 55% rule on dissolution is the stitch up of the century but it strikes me that it is evident that the people who put this together and are now in government are, how should I put this, a bit stupid?  The relevant text in Con Lib deal goes as follows:

The parties agree to the establishment of five-year fixed-term parliaments. A Conservative-Liberal Democrat coalition government will put a binding motion before the House of Commons in the first days following this agreement stating that the next general election will be held on the first Thursday of May 2015. Following this motion, legislation will be brought forward to make provision for fixed term parliaments of five years. This legislation will also provide for dissolution if 55% or more of the House votes in favour.

In a well argued piece by Louise Balldock it is clear that they the Tories are trying to make it impossible to oust them from Parliament even if the coalition falls apart, they alone could put up more than 45% of the votes, rejecting dissolution.

But this is the stupid bit.  They can’t rig votes on bills, so if the coalition does fall apart and there was a majority in favour of dissolution all they would have to do is vote through an amendment to this crass Act restoring the principle, up until now delivered through convention after the passing of a motion of no confidence, of a simple majority for dissolution.  Makes you despair.