Shove I agree with grouchy. I feel the Scottish referendum was far worse, although I have to say, the murder of Jo Cox trumped everything. That single moment dwarfed everything.
We had campaign offices trashed, MPs heckled unpleasantly with loudhailers wherever they went, horrible horrible language used towards anyone voting No - traitor, quisling. I didn't ever see a No poster that was untrashed, but every single Yes poster was intact. We were told we were feart, and that we were talking Scotland down. It was suggested we only voted No because we thought Scotland was 'too wee and too poor' (in other words, we lacked patriotism and loyalty to Scotland). Really really unpleasant stuff. Repeated over and over again. And bear in mind as well that the campaign went in for a very very long time. In fact, even now, we still have homemade Yes structures in fields around us, and people do still have stickers on their cars etc.
My lowest point was when one of the 'No' booklets was circulated around by Yes friends who were bantering on about how there were no red heads in it on Facebook. I.e. No 'proper' Scots represented. Same people routinely now, in political debate, refer to their kids red hair. (My kids do not have red hair and they also have a non-Scottish mother). Can you imagine how this reads to a person like me who comes from Southern Africa where 'whiteness' was once codified by the right kind of hair among other things. Incidentally, I stopped speaking to these people and probably never will again.
I couldn't watch the results. I went to bed literally quivering. DH stayed up and at 4am he woke me up to say it was almost certainly a No result. But he was raging. He was pacing the floor, so angry I thought he was going to cry, saying, "Right, I want my fucking flag back. They've stolen my fucking flag. I have as much right to that flag as anyone". Because the saltire was co-opted as a symbol of Scottish nationalism rather than a flag for everyone.
The thing is, people I know who voted Yes really don't recognise how deeply and painfully their 'positive' campaign scarred people. They dismiss all this. Which is why I think they'll have a very very hard time persuading them to switch to Yes.
... Except, that is, if there is a Brexit.