Thugs in London and NewYork

Metropolitan police of London is one of the best police in world, The Scotland yard is famous for his investigation, but in one thing i think its fail, i know its not failed, but i feel one thing very badly on London's street in night, the fear of thugs and hoddy gang,you don't feel safe mostly in tube stations and London's boroughs, these gangs are of mostly teenagers and most of the time without any reason they attack on you and rob you and stab you.
Three times i face these gangs ,two time in buses and one time on New Year night between 300 thousand people. First two times no fight but last time we fight with them ,i was wondering that why these gangs target me , i m still thinking about this. may be i look very rich ,hummm.i wish :(
New york was famous for its no goes areas and when ever someone visit New York Friends advice us that don't go outside after six and if you have to go than put some dollars in your pocket,in case some one fancy you for money and if you have nothing to present them, than you can get stab and hit for this reason ,but some one told me that we Londoners snatch this title from New Yorkers and now we live in more dangerous place than New York.During writing this Post i am also seeing CSI New York and same story on it, a girl is in trouble in subway.But what ever i like Met Police too much, they are very nice and gentle man, they talk very nicely and politely.I wish to join Scotland yard.I
like their Uniforms too much.