In one sense, Jim, migration is highly restricted even within the EU. Most people don't want to up sticks and leave the country of their birth and their families behind. That is a massive brake on the movement of people. The way the Ukippers and all the other other little Englanders talk (or, in one case here, a little Scotlander) you'd think that the whole continent was charging gleefully towards our borders to take us over and occupy all our houses and steal our jobs and live on benefits and probably eat our babies into the bargain. Well life's not like that. The numbers of people on the move will rise and fall according to economic and political vicissitudes, just like they've always done down the centuries. People in the end regulate themselves. If numbers hit a high for a few years, we either moan and groan about it and try to turn everyone into little racists (the UKIP and Tory right method) or, as we've always done in the past, we adapt.