Well, unless I've got hold of the wrong end of the stick the whole EU thing allowed EU citizens the right to move freely through member states and settle? Common currency (nearly) and a common passport.
Take that back to the immigration topic that gets everyone riled.
We need immigrants, both professional and unskilled. However unfettered immigration is not a good thing. I have no problem with economic migrants either, they want to work and establish a life within the UK and contribute.
The problem comes with the minority who are (a) disrespectful of our laws (b) operate criminal activities (c) think the Uk is a benefit utopia.
And I know someone is going to pluck some figures out to say (a) (b) and (c) are rare, and I agree they probably are a rare occurrence, but nonetheless they do occur. I could link umpteen news reports to East European prostitution rings, Chinese triads and chain gangs (thinking cockle pickers) and Somali rapists and so forth. Then you have the knock on that they cannot be deported - as I believe they should be because they have not adhered to the laws of this country - because of some Human Rights infraction, usually they have a child with a British born woman, which secured their right to stay in the UK, or some other whimsy - such as the Mulsim rapist who successfully argued against his deportation because he had a tattoo of a semi naked woman and would thus be stoned in his own country.
It is those situations that get people riled, and when you have successive press stories about a particular country, or nationals of a country, or indeed live on the edge of a 'ghetto' style area and you see the youth gangs of those countries re-establishing themselves for lawless purposes - because authority is frightened to say "No! this style of living is wrong, integrate" for fear of being called racist.
I have no issue with anyone who wants to come, work, contribute and enrich my country at all.
Britiain is a migrant population from Romans, to Vikings, to Franks, to Normans, to Huguenots, and in recent history (post WW2) the influx of Jamaicans, Asians, and Poles.
Immigration is what makes Britain vibrant - but it cannot go unfettered.
We are an island, we are sinking under the weight. In the 1600's the population was 4 million, today it is 64 million. That is due to longevity of the population and advances in medcine.