I take issue with your assertion that this referendum was "free and fair."
In the UK, it is illegal to tell lies about a political candidate during an election campaign in order to sabotage their candidacy. There is no similar law that makes it illegal to tell such lies in a referendum campaign.
The EU referendum campaign was, in my view, defined by people telling the public whatever they wanted to hear to get the result they desired. I don't think that any democratic process can be defined as "free and fair" or even genuinely democratic when significant campaigners set out to spread misinformation so that the voters weren't making a genuinely informed decision.