Both campaigns were guilty of misinformation but the most blatant outrage was the UK government itself spending £9 ($12) million of the British people's money producing and delivering one-sided pro-EU propaganda to every address in the UK.
Edit: For people downvoting the above factual post:
Government's £9m EU 'propaganda' leaflet has left public LESS well informed, study shows:
I don't know why you're being downvoted. The lack of impartiality in the public debate was pretty obvious, there was almost nobody in the public sphere that was openly exploring all the issues. Would it have been hard to actually listen to each other and get beyond the surface level shouting match that constituted the pre-Brexit debates?
> 'propaganda' leaflet has left public LESS well informed, study shows
Two polls at different points in time, without any information about methods and sampling error, gave slightly differing results (23% vs. 21%). This leaflet campaign took place between them. This isn't a very good argument: Weak correlation in noisy data does not mean causation.
(Not saying the government was right to do this this way. But calling the thing misinformation that confused voters based on this comparison of polls is a bit exaggerated.)
The funny thing is that it back fired. People were sick of these kind of expert opinions and interference. This pamphlet probably turned people over to the leave side.
I think it would have been better to make an emotional argument instead of relying on facts. People don't vote objectively. This is rubbish propaganda.