I remember all the bookies were wrong in the Irish refererendum.
Paddy Power had even paid out on a win :p
Guess I should laugh, but Paddy Power was right in the end I suppose.
My suspicion is that the betting is being jiggered for propaganda purposes.
If your economic interests are in the many billions of pounds, then what’s a few million in bets for “remain” to generate a propaganda point? Bookmakers are really neutral in this; they match bets and take a cut. It’s already been noted by Ladbrokes (major bookmaker in UK) that the average bet for “remain” is much higher, but there were many more bets being placed on “leave.”