Results could be known in @ 12 hours. There are gonna be no official Exit polls, only surveys of known voters of how they voted, which may well be wrong as the word is huge numbers of people who haven’t voted for decades are going to vote.
None of the Pollsters know who or where these people are, so can’t poll them. Turnout is key, a big turn out and lots of those ex non voters are active and probably voting out. So we really will have to wait until we see real votes coming in.
Plus we have this
Google Predicts Landslide Win for Brexit Leave
https://investmentwatchblog.com/google-predicts-landslide-win-for-brexit-leave/
I don’t know how accurate they are…but that makes sense talking to people.