So if Corbyn was barely doing anything, and Farron was crusading around the country rallying the faithful, why was there only a 3 percentage point difference between them?
Brexit is on the Conservatives. No one else.
Alright, back of envelope calculation. Say both the LDs and Labour got 65% of their vote to back Remain. So 35% of each vote share is:
LD - 2.4m * 0.35 = 0.84m leave voters
Lab - 9.3m * 0.35m = 3.29m leave voters.
If 650k people had voted a different way, Brexit would not have happened. That would require the LDs to have convinced 77% of their remaining leave vote, but Labour only had to convince about 20% of its own leave vote.
Add in the aid to the entire BSIE campaign had Labour not done its own thing for absolutely no reason, add in the profile of the entire Labour front bench telling all those Labour voters that Labour's top brass absolutely thinks you should remain.
The Tories hold the blame for the brunt of Brexit, but I put the blame for the pro-EU side failing at Labour's door. Had Corbyn and his team done more, at the very least the result would have been much tighter.
Labour has reach where other party's don't - in Leave-voting areas of the North and the Midlands that the LDs and Cameron simply could not reach.