Actually they weren't the most heavily armed people I've seen or the closest they've been to my home. A few years ago, the ICC in Birmingham City Centre paid host to the G8 conference of the world's 8 wealthiest countries. You may remember Bill Clinton having a pint in a Birmingham Pub:
I lived a mile from the ICC.
There were machine gun toting, body armoured police at the end of my street for the week. made me slightly uncomfortable. British Bobbies really shouldn't look like that. And machine guns are MUCH scarier in the flesh.