I’m not aware of a super-majority requirement for the referendum to pass and 75% voter turnout compares favorably with voter turnout in European countries.
The REMAIN camp is clutching at straws. They’re livid because they lost.
There was nothing at all about a required figure for turn out or to win by any particular percentage. This is all being made up only now after they lost the vote.
You can’t even divide this along party lines. I would say that a third of liberal party folks are supporting the leave-effort.