One big issue you face when traveling to bigger cities is pickpocketing. In case you don't know what pickpocketing is I will let you know. It is simply a person that steals something from another person without that person noticing. Usually a pickpocketer will try to steal a wallet or money, I.D.s, or other things of values.
I used to think well how dumb do you have to be in order to not feel someone stealing something from you, especially if that item is in your pant pockets or around your wrist or neck!? How you can't feel, I don't know, but I guess some people are just skilled in not being noticed when they don't want to be. Pickpocketing doesn't always have to be taking something from someones pant pocket though. You can also have stuff taken from a bag or even have jewelry taken off your wrist, neck, etc.
I have my fingers crossed that I am not a target or a victim of pickpocketing while in London. But I will keep you all updated!!!!