You mean the areas not controlled by Muslim extremists, don't you? Since Fox News reports that many of these cities have "no-go" zones where Christian folks fear to tread - unless they want a curry..
Then there's the Irish areas and the Polish plumbers, and the Spanish football managers - not to mention the enormous army of Aussies in London! Did I mention the French - who are massing in a country only @@ miles from Dover? And what stops the Scottish hordes crossing into our fair English cities? Ever heard of McDonalds?