I agree that it's a foregone conclusion: I believe that the result would be to leave the EU, because majority popular sentiment leans that way.
Unfortunately this is based on the majority of the population having little to no clue of any serious, sober, thoughtful cost-benefit analysis of EU membership. The vast majority of people have absolutely no idea of what the positives and negatives of membership actually entail and fill that vacuum by falling back on popular press sloganeering, vague half-formed ideas and everybody's favourite, gut instinct. A referendum held tomorrow or next week or next month would on that basis be a landslide "No" vote. The only remote possibility of changing this state of affairs would be if the government were to produce, in the form of a leaflet or some such, something which could educate the public in clear, simple, jargon-free language an impartial, disinterested, neutrally-couched explanation of what EU membership means and what exit would mean, delivered to every household in the realm as has been done before on occasion.
Staying in may well be the best option. Coming out may well be the best option. But for Christ's sake, let's have an informed populace capable of making a truly informed decision.