All the way along the Northern Line route is the same now with Tooting being the worst. I worked in Balham (Gateway to the South) for a few years back in the 60's and it was quite a nice area then. I often walked up to Tooting and had a couple of friends that lived there.
My daughter bought a car from a dealer there a few years back and I went with her to pick it up. I couldn't believe how much it had changed. What a dump.