i wouldn't say jamaicans run anything in london
there are some places like brixton full of them
of course on local scale, but almost all groups in london operate in a local scale, included turks in their neighbourhoods
Pretty much 75% of the Jamaicans in Brixton/London are old men, it's the Jamaican/African's children that run the streets of every predominantly black area in London, little teenagers that run around stabbing and shooting each other, pathetic really.
