The Tories played dirty and they still lost.
We’ve had two by-elections since the brexit vote (I’m excluding Jo Cox’s constituency’s by-election as the other parties rightly decided not to run candidates), and both have shown massive swings away from Tory incumbents towards the Lib Dems.
This is significant because the Tory vote share in 2015 was not notably higher than it was in 2010; it just happened to be concentrated in formerly Lib/Con marginals. A swing back to the Lib Dems is seriously bad news for the Tories, especially if they’re also planning to engage in extremely high risk politics that has the potential to destroy them if it all goes wrong, like, I don’t know, brexit.
There is still a lot of mileage in opposing brexit. Except the Greens, who are not really significant in terms of vote share, the Lib Dems are the only pro-remain party. Those of us who think brexit is the single most important political issue and support remain have only one option – the Lib Dems. Leavers get to choose between the Tories, Labour and Ukip. In FPTP that means the LDs sweep up a lot of seats, because theirs is the only vote not being split. Divide and conquer.
Plus, we are beginning to see cracks forming in the Tory party’s unity as both Boris and David Davis(!) are making suggestions towards a softer brexit, which has offended the hardliners like IDS. It’s a long way from over.