On the other hand being a member of the EU is very serious business from a constitutional point of view.
Given this point of view it seems just as reasonable to require a super majority for staying. I.e. unless the wast majority is comfortable with deligating (a very significant amount) of power to the EU, why should it be allowed?
I'm proposing that a supermajority should be required for changes either way. Since the UK is already in the EU, you'd need a supermajority to leave. This builds some hysteresis into the system to reduce short-term swings.
Note that a referendum was held shortly after the UK joined the EC, and that was 67% in favor of it.
