All of my friends who are economists (including several in the UK) are pretty concerned, as am I, although sadly none of us are particularly surprised as this is what happens when people are allowed to vote on things they do not understand. And yes, I realize that sounds terribly elitist, but I do not believe in governing by referendum because, and again I'm sorry for being so blunt, this is a far more complicated issue than the average person can understand. It is why we elect leaders, and to be derelict in one's leadership at the most important juncture is cowardice, in my opinion. It's a reactionary mistake that will have economic ramifications not only on the economy of the UK but far larger impacts on the US economy than most people realize, ranging from a flight to the US dollar that will hammer our exports to increased inefficiencies in global trade.
I do think this will lead to a breakup of the United Kingdom, as well, and it will be interesting to see if Northern Ireland elects to leave and rejoin Ireland. I think it's safe to assume that Scotland will leave the UK and remain in the EU. If either or both of those happen, the impact on the UK (or, at that point, former UK) economy will be devastating.