Not to get too deep into this, but I'd imagine that a lot of the border/airport security is completely missing the point, in as much as many potential perpetrators of such terrorist acts are most likely already living here. And are probably British citizens to boot.
Hopefully, common sense will one day prevail (although I'm not holding my breath) and the myth and deception of 'multiculturalism' is finally consigned to the swamp it crawled out of. If you import a stone age 'culture' into your country, then foster, enable, encourage and protect it, it can be no surprise that, eventually, aspects of it will start to manifest themselves in day to day life.