No one can say with even the remotest degree of certainty whether staying or leaving will be better for the long term interests of the UK.
However it seems to me that purely on a risk assessment basis, to leave is seen by many as high risk, as the future consequences are unknown and to stay is considered either the lower or no risk option based on our knowledge of our current position within the EU. Better the devil you know etc. So in effect the choice is:
Vote to leave - decision based on our possible speculative future position.
or
Vote to stay - decision based on the known current position.
Now whilst I accept that there is considerable risk attached to leaving, anyone who feels that to remain is the safest bet should consider just how much the UK has been changed by our involvement in the EU since the British electorate voted to remain in the Common Market. No one voted for the uber powerful, unaccountable, often dictatorial, expensive, aspirational super state that we now find ourselves involved in. IMO, when looking at the risk level attached to voting remain, it's worth comparing like with like (potential future with potential future) and contemplating what GB might look like in a few decades time. Yes, we know what the EU is and our position within it now but that will change in the future and so will our position within it. How will the current political issues currently effecting the electorates decision e.g loss of soveriegnty and uncontrolled imigration to name but two have effected the UK in twenty thirty or forty years time? Will we be sorely regretting our decision to remain, if that is the way the vote goes?
I have long felt that despite the risk, and providing that we remain as a United Kingdom, the UK's long term interests are more likely to be rosier outside of the EU. However I have promised myself that I would listen to all the arguments from both sides before finally making up my mind. So far I have heard very little to pursued me to change my mind. In fact all of the dubious scare predictions along with the recent crude US attempt to blackmail the electorate into voting to remain has so far only strenghened my view.
Just my opinion.