Well Leave is doing better than expected and is currently leading by around 4%. However many London areas yet to report and they are expected to vote remain.
Only prediction from me at this stage is it will be very close.
UPDATE: I think Leave may have done it. Their lead is now over 700,000 and growing. Not certain but would need some large margins for Remain in remaining areas to pull that back.
UPDATE2: BBC and ITV have called it for Brexit. Today is UK Independence Day.
Doubt Cameron will survive even a year.