[evgen]

Thinking about this more I am convinced Farron is on the right track. The leave/remain issue gives the LibDems an opening to expand and they should take it, there is no future in being 'not nasty enough to vote Tory but not dumb enough to vote Labour' and if both parties are willing to surrender an issue that at one point had the support of 48% of the country (and concentrated in a few areas to make campaigning easier) then you go for it.

Without such a gamble the LibDems will remain in the also-ran group with UKIP and the Greens. You push any issue that gives you a wedge and use it to crack a few ridings and if necessary you write off the 1/3 in the hope of picking up 2/5 of the two larger parties.