The guy speaking is a far-right UK politician - the kind that's too far right for UKIP. He doesn't seem to be providing any evidence, only his opinions and anecdotes. There is no shortage of alarmists of his kind in this country and fear-mongering is obviously in-fashion right now. That's why we have Brexit.
"The fact that a believer is happier than a skeptic is no more to the point than the fact that a drunken man is happier than a sober one." - George Bernard Shaw
