We don't need to be in the Eu to let qualified people come here to do work. In fact being in the EU tends to restrict bringing people in from Non Eu countries. Why should it be easier for someone from Romania or Slovakia to come to the UK to work rather than someone from the USA, Canada, Australia, New Zealand..........if we leave we can pick the best from wherever, maybe even the UK........
It's not qualified people we need, though. In the main we produce enough of these. The vast majority of immigrants coming here from Romania and Slovakia etc. are coming to work in minimum wage type jobs. I can't see many people from the USA, Canada, Australia or New Zealand coming over for those. I work in the food industry and that would be changed completely without immigrant - particularly Eastern European - labour. The majority of food manufacturing sites now have work-forces that are predominantly non-British. Without them the industry would collapse or prices would rise dramatically.