Hey that's my blog! When I saw bushcraft UK as an incoming link, I had to look.
Truth be told, guys, I never set out to camp in cities. I say in the original blogs that I avoid it like the plague. But I like to take ridiculously long walks (9 months was my longest). And there usually aren't trails or a easy row of sanctioned campsites between points A and B, so I've camped in some very strange places. Sometimes, you have to sleep in a city.
Well, the post brought me back. I'd been totally without internet forever it seems, and had forgotten all about this forum!
And I would say that "inner city" bushcraft is simply knowing the skills to survive unassisted in your environment. I've spent lots of time with the homeless, particularly disabled vets, and let me tell you, you can learn a few things about the wilderness from those guys, but they know more about the cities around them than anyone.
Being a "bum" or "wino", however means being "worthless" or a "drunkard", two types of people you will find on the streets, but by far not the majority. It would be akin to comparing bushcraft to heading out with a motor home and a generator. They are not the same thing, though they are done in the same places.