He was born in Britian over FIFTY YEARS ago.  

If you truly think this is about immigration it's too late.  First off, even if you halted all immigration today, you'd have to wait 50+ years to see the effect.  Second, it wouldn't matter anyways because many Muslims already live here and with the internet and all, can still be radicalized here.

I.e., it's far too late to solve this problem by shutting down immigration.  That ship sailed decades ago.  Now it's time to focus on real solutions.