England once had a very effective method of dealing with 5th Columnists of this ilk.
It is amazing. These socialist-driven countries let them in, then whine about it. What in the heck did they expect?? And there will be more, around the globe, as long as these radical Islamo-freaks are allowed to function in the countries they hate....
They were 'let in' because at one time their homelands were part of the British Empire or Commonwealth, and as citizens of that Commonwealth, could move freely among them. Most originally went to the UK as low level workers to "do the work Brits won't do." Generations later many are still low level workers or living off of what has become the Socialist dole.