Meanwhile, nearly half of all voters believe there are plans for further EU integration and enlargement that are deliberately being withheld until after the referendum, with 49 percent saying it was probably true. That number jumped to 75 percent once accounting for only vote leave supporters.
There will be no official exit polls from the referendum, leaving the world to wait until ballots have been counted. However, a small proportion have speculated that the U.K. broadcasters BBC and ITN held back from commissioning exit polls in order to allow the vote to be fixed without anyone telling, with 15 percent of all respondents in the YouGov poll saying it was probably true, while 44 percent said it was probably false.
That's versus 22 percent of leave voters who say it is likely true and 10 percent of remain supporters.
Voting in the U.K. referendum will run from 7:00 a.m. to 10:00 p.m. London time Thursday, June 23.