I'm not thick or racist or particularly old.
I come from another country but have been living here for 30 years, and it seems to me that the British never fully bought in to Europe.
We don't appear to like the French or the Germans, we never adopted the currency, we are bitter that our way of life is modified by EU rulings and constantly mutter about how stupid these rulings are.
If the European union continues to grow, pulling in countries that are borderline european, but almost universally with tenuous economies, I don't think it's in our best interests to continue to support it.
I have absolutely no problem with immigration, as long as it's beneficial, and/or humanitarian.. and there is no reason why having a visa should stop anyone from coming here as long as they can contribute ( I also have a problem with British who's family business is benefits, but that's another argument).
Clearly, as citizens of the world, in extreme humanitarian circumstances we should take the disenfranchised and those fleeing from oppression, but this could be managed with a European caucus.
The other concern I have is the formation of a European Army which brings me back to my first point. Do we trust anyone other than those we shared an empire with because we don't appear to.
We are strong, resourceful, have many trading partners excluded by the current tariffs waiting in the wings, and I think as a nation we would lose a degree of resentment against the EU that it possibly takes a non-native to see.