Immigration will be used by Brexit greatly come the run-in and it will turn dirty and nastyJust heard on the wireless that the single biggest issue for those intending to vote leave is immigration, and that is what I expect the Brexit campaign to major on in the run up to the vote. Of course they need to be clear that actually imposing controls on immigration from the EU firstly requires a UK Government prepared to do it, which is not a given, and secondly rules out membership of the EU internal market where free movement of people is a given (so no Norway/Switzerland type deal with the EU). I suspect the sovereignty stuff is just too vague for most people, especially the undecideds, to have top of their list.
