Democratic Unionists
They should be possible to deal w/.
PC won't work w/ Tories, it's just very unlikely. Nor would it help much. Even if they manage to get some sort of a coalition, incorporating everybody but LD and Labour, it won't be stable. Even if nobody defects, over an average parliament, any gov't usually looses a few MPs due to natural causes, leading to by-elections, which it not infrequently looses. LDs are the only ones capable of providing any modicum of stability. And they won't cost more than the mutually exclusive demands of a wide array of minor nationalists.