Some places in London have a bad reputation such as: Stratford, Brixton, Peckham, but it's not always the case. If you act like a tourist and wave around with your camera, you could be robbed anywhere.
If the worry is crime, be cautious of Oxford Street. Lots of pickpockets. Many police cars can be seen in Brixton. Stratford has become more dangerous over the last few years. Many people have said they would not want to live in Acton.
Try and avoid going to Picadlly Circus. It is very crowded, dirty and filled with many tourist but also many pickpockets. I was mugged and all my money stolen. There were many gypsies and they like to pray on strangers. Also avoid Hyde Park after dark. The freaks come out at night.
The worst parts are to the East - avoid Plaistow, Hackney, E16.
Brixton is not good, but it's better than people say.
Always dress down, or take a cab.
