Same response I gave the other guy - you can go look up the market here rather than conjecturing [1]. It was about 25% the day before. In any case, it seems very silly to discount prediction markets because the probability didn't work the way you expected it to in a single event. The whole point of probability is that it's probabilistic!
If that were true then the results of prediction markets wouldn't closely track the actual results that happen, as the link I provided shows that they do. Also, you could be making tons of money right now! How's that going?
[1]: https://www.predictit.org/markets/detail/1413/Will-the-UK-vo...