Well this certainly makes Haltemprice and Howden interesting. The Labour rebel MP Bob Marshall-Andrews has apparently said he's going to campaign for David Davis during the forced by-election. That's a big test for Brown authority. Technically he should have the whip withdrawn and be expelled from the party, but as Labour are unlikely to put up a candidate will Brown have the bottle to do it?
What shall be interesting when the Lords inevitably reject the 42 days issue is whether Brown will try to use the Parliament Act to force through bill. That would of course make it questionable as to whether it even had any legal status as the Parliament Act is quite clear about what it can, and cannot be used for.
In effect we might end up seeing an unelected Prime Minister who has no mandate using a tool designed to force through mandated manifesto commitments on an issue that it should not and cannot legally cover. Such an act would be a complete abuse of power by the Executive.