The Brecon and Radnorshire By-Election
This one should prove interesting.
Rumour has it that the Lib Dems will get it and cause the Tories to lose their seat because a lot of the constituents are Welsh sheep farmers who don't want to leave the EU because it would be detrimental to their livelihoods.
On the other hand, they will vote Tory because Chris Davies has done a good job since 2015 and got caught out over a silly mistake on his expenses. Plus, their constituency voted leave (marginally) in the referendum and Boris has promised to make sure their farming is looked after post Brexit.
Interesting times ....