I'm guessing that should we Exit the EU in line with the result of the referendum the next thing will be rising calls for another referendum to take us back in again. This story has got real legs!
It was 1973 when the UK joined the EU in the form it was then. That too was decided by a referendum, and ever since then there has been disagreement about whether we should stay or leave.
Since the leavers continually lobbied for 43 years about leaving, I think that we can also expect that there will be discussions about rejoining for a similar timescale.