My working hypothesis is that they were certain they weren't getting a majority and so could put it in as red meat for the back benchers and then say "sorry, couldn't get it past the Lib Dems".

And now they're stuck with actually doing it. I wonder if Gove's been told to go away and come back with something so appalling that there will be enough Tory rebels to kill it at second reading and then they never have to worry ever again. Plenty of people will believe that Gove produced something appalling on purpose because it's Gove.