Protecting an address

On the way back to my hotel, I ran into four of these guys, prowling the street in what seemed to be a perfectly ordinary neighbourhood. I saw one, then two, then rounded the corner to see a third. I couldn't stand it any longer and asked #3 what was going on. 

"Oh, we're just protecting an address," he replied calmly. He was happy to let me take his photo and to show me what he was carrying -- an MP5, a sidearm, and a Taser. And a baton. I later did some googling and learned that this is a special branch of the Met, whose job is to guard the homes of diplomats, visiting VIPs, etc. I guess with all the Bentleys, Aston Martins, Lamborghinis, Maseratis and Ferarris parked along the streets, I should have guessed there were some bigwigs in the neighbourhood. 

And here I thought they were just oil rig workers.