Again a misleading statement The UK can refuse entry to EU citizens as they have done already. In fact they have refused entry to over 110k Europeans since 2010.Very good but completely missing the point entirely, which was that while being in the EU we don't have total control of immigration.
http://www.bbc.co.uk/news/uk-politics-eu-referendum-36101449
A European citizen cant come some to the UK and immediately claim benefits they have to have private health insurance and a means to support themselves . Our Government kindly disregards these rules and lets them have free care and gives them social care but it does not have to under Euro law.
On the 14th June 2016 before the referendum Europe’s top judgesbacked Britain’s right to refuse to pay family welfare benefits to unemployed EU migrants who have been in Britain for less than five years.
UK already had all the powers it needed .