One time on one of my very rare visits to London I was walking down Whitehall & he was coming the other way in a little group of 5 or 6 people. I could have said something to him, I passed close enough, but he was only the mayor of London then not the Prime Minister, & I didn't dislike the pasty faced little fucker quite as much as I do now, so I let him be.
For sure the couple of bodyguards kept themselves out of the picture, not to mention the backup squad. I'd like to know what the guy was saying to him......