Re: brexit cost
"This control of "benefit tourism" is exactly what the UK government has been pressing for for many years, but the EU consistently refuses to accept it."
I'm not an expert, but I rather thought that you can deport EU citizens if they haven't found a job and are unlikely to find one. http://www.bbc.com/news/uk-politics-eu-referendum-36449974
Similarly, when Germany wanted to deport an EU citizen (Romanian) who was only interested in claiming benefits rather than working, she appealed the case all the way to the EU Court of Justice which agreed with the German authorities. So I don't think this point is valid. http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A62013CJ0333
Furthermore, as far as I am aware, migrants are less likely to be claiming benefits than UK citizens. According to http://researchbriefings.files.parliament.uk/documents/CBP-7445/CBP-7445.pdf just over 2% of benefits claimants are citizens of other EU countries. If we assume that EU citizens make up about 5% of the total UK population this means that they're half as likely to claim benefits as UK nationals.
Please do check the numbers and let me know if I've overlooked something.
Biting the hand that feeds IT
