Some very ignorant people voted Leave to keep johnny foreigner out. And before every Brexiteer starts bleating I know some voted Leave for other non-immigration related reasons (however misguided).
There are jobs that British people mostly won't do. Picking fruit and veg in fields. Working in meat processing factories (read Des' posts about the workforce being 100% from Eastern Europe).
Our NHS relies on overseas professionals.
Why don't those that voted Leave go and do these jobs that they said were being taken off us, if they are so concerned about johnny foreigner coming in?